An infectious disease is a disease that is caused by the invasion of a host by pathogens（病原体）whose activities harm the host’s tissues and can be spread to other individuals.
Microorganisms（微生物）capable of causing disease are called pathogens. A true pathogen is an infectious agent that causes disease in any possible host. The terms “infection” and “disease” are quite different. In order to cause disease, pathogens must be able to enter the host body, stick to specific host cells, invade and multiply and do damage to host tissues.
Pathogens may be spread through either direct or indirect contact. Direct contact occurs when an individual is infected by contact with the infection source. It also includes taking in the infectious droplets released by sneezing or coughing. Indirect contact occurs when a pathogen can survive the environment outside its host for a long period of time. So lifeless objects that are polluted by direct contact with the infection source may be the indirect contact for easily infected group.
Public health measures typically involve killing the pathogen from its source or from its route of spread. Those measures include ensuring a safe water supply, effectively treating waste water, and initiating animal control and vaccination（疫苗）programs, etc. Personally, the first line of defense is to keep pathogen at bay by following good personal hygiene（卫生）habits. Prevent infection before it begins and avoid spreading it to others with some easy measures, such as washing hands, getting vaccinated and so on.
Man never stops fighting against all kinds of infectious diseases. But in the past two decades at least a dozen “new” disease have been identified, and traditional diseases that appeared to be “on their way out” are re-emerging. Globally, infectious diseases remain the leading cause of death. Clearly, the ballet has not been won. Nevertheless, it is increasingly difficult for most of us to deny the claims of science. We are continually presented with great amounts of relevant scientific and medical knowledge, which encourages us to take more responsibility for our own health.
1. What does paragragh 2 focus on?| A．Origin of true pathogens. |
| B．Nature of infectious diseases. |
| C．Strategies for avoiding tissue damage. |
| D．Differences between infection and disease. |
| A．Getting bitten by an infected dog. |
| B．Playing toys a sick child played with. |
| C．Breathing in tiny drops from sneezing |
| D．Shaking hands with an infected person. |
| A．At risk. | B．Off course. |
| C．Under control. | D．Within reach. |
| A．Man is at a loss about infectious diseases. |
| B．Traditional infectious diseases are dying out. |
| C．Science counts in defeating infectious diseases. |
| D．The battle against infectious diseases is in vain. |
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【推荐1】Staying positive through the cold season could be your best defense against getting ill,a new American study suggests.
In an experiment that exposed healthy volunteers to a cold or flu virus,researchers found that people with a generally sunny character were less likely to fail ill.The findings,published in the journal Psychosomatic Medicine, build on evidence that a “positive emotional style” can help ward off the common cold and other illness.
Researchers believe the reasons may be both objective―as in happiness improving immune function―and subjective―as in happy people being less troubled by a sore throat or runny nose.“People with a positive emotional style may have different immune responses to the virus,” explained lead study author Dr Sheldon Cohen of Carnegie Mellon University in Pittsburgh.“And when they do get a cold,they may interpret their illness as being less severe.”
Cohen and his colleagues has found in a previous study that happier people seemed less likely to catch a cold, but some questions remained as to whether the emotional quality itself had the effect.
For the new study,the researchers had 193 healthy adults complete standard measures of personality qualities, physicals health,and emotional “style”.Those who tended to be happy,energetic and easy –going were judged as having a positive emotional style,while those who were often unhappy,tense,and hostile had a negative style.
Afterwards,the researchers gave them nose drops containing either a cold virus or a particular flu virus.Over the next six days,the volunteers reported on any aches,pains,sneezing they had,while the researchers collected objective data.Cohen and his colleagues found that happy people were less likely to develop a cold.
What’s more,when happy folks did develop a cold,their symptoms were less severe than expected based on objective measures.
On the contrary,people with negative characters were not at increased risk of developing a cold based on objective measures,though they did tend to get down about their symptoms.
“We find that it’s really positive emotions that have the big effect,” Cohen said,“not the negative ones.”
So can a bad-tempered person fight a cold by deciding to be happy?
1. The purpose of Cohen’s new study was to .| A．find effective ways to fight illnesses |
| B．test people’s different immune responses to cold virus |
| C．tell differences between happy people and unhappy people |
| D．examine whether health was related to emotional styles |
| A．get close to | B．keep way from | C．get used to | D．go on with |
| A．By comparing the experimental results of different groups. |
| B．By asking the volunteers to complete a form. |
| C．By collecting data among people with a cold. |
| D．By observing the volunteers’ symptoms. |
| A．an emotional style is difficult to change | B．happy people are immune to cold virus |
| C．people attitudes towards illnesses are different | D．happiness itself helps protect people from cold |
【推荐2】The Secrets of Sleep
Have you ever wondered why you spend so much of your life asleep? Just as electricity charges the battery of a mobile phone, sleep recharges your body and your mind.
What is sleep?
Why do people need to sleep?
Humans could not function without sleep. According to the Royal College of Paediatrics and Child Health, sleep helps people learn by strengthening their memories. It has physical benefits too—like maintaining a healthy weight and boosting your immune system.
What are dreams?
Dreams usually occur during a stage of sleep known as rapid eye movement (REM) sleep. In REM, the eyes move quickly back and forth and brain activity increases. Scientists are not sure why people dream.
How much sleep do I need?
Most adults need around eight hours of sleep a day, but Mandy Gurney, who runs the Millpond Children’s Sleep Clinic, says that children need more.
| A．When I wake up, I am reborn. |
| B．I really think I need more sleep than now. |
| C．Sleep is a natural and temporary state of rest. |
| D．Some say it is a process that helps store memories. |
| E．Too little sleep can make you tired and bad-tempered. |
| F．You become healthier and thus diseases will not bother you. |
| G．Sleep is more vital for children because their minds and bodies are still developing. |
【推荐3】The U. S. Food and Drug Administration (FDA） has approved a debatable Alzheimer's treatment, the first that promises to slow the disease's destruction in the brain.
The drug, aducanumab, is also the first new Alzheimer's treatment approved since 2003.However, in 2019, aducanumab was nearly abandoned after it appeared unlikely to succeed in two clinical trials. But after reanalyzing more data, the drug's developer Biogen saw signs indicating the drug might work, and decided to pursue FDA approval.
Still, today's decision concerns some doctors and scientists because they aren't convinced that the drug actually works. Approving a drug that's not effective would offer patients false hope, those experts argue. “This is a great day for Biogen but a dark day for the field of Alzheimer's research,” says Michael Greicius, a neurologist at Stanford. Pushing forward on the “illusion of progress,” he says, “will come at a cost to genuine progress in finding an effective treatment for this destructive disease.”
Others disagree that the evidence is slim, and are excited about having a new tool to fight a disease that has escaped an effective treatment for so long. “We have been waiting decades for this,” says Maria Carrillo, an expert at the Alzheimer's Association. A drug that delays decline due to Alzheimer's promises patients “to sustain independence and to hold onto memories longer,” she says.
The drug targets the sticky protein—A-beta（淀粉样蛋白). Some researchers suspect that in Alzheimer's, A-beta confuses connections between nerve cells and damages brain tissue, ultimately causing Alzheimer's symptoms. But that idea is still unsettled. Brain scans reveal that aducanumab is effective at reducing A-beta in the brain. What's less clear is whether this reduction comes with consistent improvements in people's quality of life.
1. What does paragraph 2 mainly tell us about aducanumab?| A．Its bitter failure in clinical trials. |
| B．Its tough path to getting recognized. |
| C．Its medical value in treating Alzheimer's. |
| D．Its challenging process of being produced. |
| A．Proof. | B．Significance. | C．Prospect. | D．Misunderstanding. |
| A．Unconcerned. | B．Doubtful. | C．Positive. | D．Intolerant. |
| A．A-beta in human body should be removed. |
| B．Aducanumab has potentially serious side effects. |
| C．A-beta's decrease improves people's quality of life. |
| D．Further tests on aducanumab need to be carried out. |
【推荐1】Scientists have not found any signs of life on Mars yet,but they say a robotic vehicle called “Curiosity” is helping them learn a lot about the planet’s history and climate.
Curiosity landed on Mars in August 2012 after travelling through space for more than eight months.It was sent to Mars by scientists from NASA in the United States.
Curiosity is about the size of a car and has six wheels.It also has a robotic arm,cameras,and instruments that allow it to examine things it finds on the surface.Then it sends the information back to the earth.
Curiosity’s main task is to find out if anything could live on Mars,either now or in the past.On Nov.2,NASA scientists held a press conference (新闻发布会) to discuss what Curiosity had found in its first two months on Mars.
Curiosity has found soil that is similar to the sand formed by volcanoes (火山) on the earth.Scientists say that studying the minerals in Martian soil will help them understand what conditions were like on the planet in the past.Curiosity also found smooth stones like the ones found on river beds and seashores on the earth,where their rough edges have been worn down by water.Mars is very cold and dry now,but scientists say the smooth stones tell them that a river used to run through the place where they were found.
Curiosity has been testing the atmosphere around Mars for a type of gas called methane (甲烷),but so far it has not found any.On the earth,most methane is produced by plants or animals.Methane on Mars might indicate that some type of tiny plants or animals lived there.
Curiosity is the fourth robotic vehicle to be sent to Mars.It will continue to explore the planet for about two years.
1. Which of the following descriptions about Curiosity is TRUE?| A．It landed on Mars in January 2012. |
| B．It is small in size and has four arms. |
| C．It took over eight months to arrive in Mars. |
| D．It was sent to Mars by scientists from Russia. |
| A．there’s no air on Mars | B．Mars is warm and wet now |
| C．the soil on Mars is rich | D．there used to be water on Mars |
| A．smooth stones | B．rivers |
| C．robotic vehicles | D．volcanoes |
| A．some tiny animals once lived on Mars |
| B．there are no plants or animals on Mars now |
| C．the atmosphere around Mars is full of methane |
| D．Curiosity is designed to test the atmosphere around the earth |
| A．Humans benefit a lot by going to Mars. |
| B．Scientists will stop the research on Mars soon. |
| C．It is possible to build an earth-like environment on Mars. |
| D．A robotic vehicle helps scientists get useful information from Mars. |
【推荐2】Even a small increase in light activity such as washing dishes, or walking around the house might help prevent an early death among older adults, researchers say.
“It is important for elderly people, who might not be able to do much moderate intensity（强度）activity, that just moving around and doing light intensity activity will have strong effects and is beneficial,” said Ulf Ekelund, who led the research.
Published in the BMJ, the latest research was based on a review of eight studies involving a total of more than 36,000 people with an average age of almost 63 years. Participants were followed for five to six years; 2,149 deaths were recorded. All of the studies involved monitoring the physical activity of individuals who had activity trackers, and the studies did not rely on self-reporting, which, the experts noted, could be unreliable.
For each study participants were split into four equal-sized groups, based on the total amount of time spent actively, and the risk of death assessed, taking into account factors such as age, sex, body mass index, and socioeconomic status. This was then repeated for an amount of activity at different levels of intensity. The results were analyzed together to give an overview. The team found a greater amount of activity was linked to a lower risk of death. The results held for different intensities of activity. The team said the study supported the message “sit less and move more and more often”.
However, the study had limitations. It only looked at the situation for middle age and older adults, most of whom lived in the US or Europe, and some of the effect could be due to those people with a higher risk of death being less likely to be related to physical activity. Physical activity levels also were only measured over one period of time.
Dr Gavin Sandercock, from the University of Essex, said the results suggested moving more brought bigger benefits than simply reducing the time of sitting, another factor measured in the study.
“This study reinforces the important message that getting the least active people to do even just a little bit more physical activity can have important public health benefits,” he said.
1. Which of the following may Ulf Ekelund suggest elderly people do?| A．Lying on the sofa reading. |
| B．Doing a little gentle gardening. |
| C．Going out to hike with friends. |
| D．Playing basketball sometimes. |
| A．It lasted about 8 years. |
| B．The researchers admitted they used fake data. |
| C．The participants didn't include younger people. |
| D．Some participants died because of doing too much physical activity |
| A．Doubtful | B．Critical |
| C．Supportive | D．Neutral |
| A．Highlights | B．Conveys |
| C．Excludes | D．Denies |
【推荐3】A cat with an accent sounds like a character in children’s tale, but Swedish scientists are trying to figure out if domestic cats actually do have different “dialects” based on their geographical location. They also want to understand if the owner’s voice might have a role to play in the way cats’ meow（猫）. If they’re successful, the team of scientists from Lund University. hope to put together a “dictionary” of cat sounds.
The project will be carried out over the next five years. SchÖtz explained that she and her team will use phonetic（语音）analysis to compare cat sounds from two parts of Sweden-Stockholm and Lund-with different human dialects, and figure out if the cats from these regions also have different dialects. They will focus on tune, voice, and speaking style in the human speech that is addressed to cats, and also cat sounds that are addressed to humans.
While it all sounds rather fanciful, the main idea behind the project is to improve the human-cat relationship. Since their domestication（驯化）about 10,000 years ago, cats and humans have learned to “talk” through audio（声音的）and visual signals. Even today, wild cats have no need for meowing in adulthood, while domestic ones continue to meow as a way of communicating with humans. And by understanding more about this communication, SchÖtz and her team hope to influence the way cats are treated in animal hospitals, shelters, and care homes.
The team will record voices of about 30 to 50 cats in different situations, for example when they want access to desired locations, when they are content, friendly, happy, hungry, annoyed, or even angry-and try to identify any differences in their phonetic patterns. They want to know if cats prefer pet-directed speech or prefer to be spoken to like human adults.
The project is yet to begin officially, but the researchers have already started testing their equipment and techniques by recording a few cats’ meowings. And they’ve already made a few interesting observations. In one of the recordings, they noticed that when a cat is begging for food its meows rise slowly. But the opposite happens when the cat is unhappy. By the year 2021, SchÖtz and her team hope to have entirely broken the cats’ code by interpreting all their meowings.
1. Carrying out the research, Swedish Scientists will mainly investigate ______.| A．how cats vary the melody of meows | B．how cats communicate with their owners |
| C．how cats meow with a funny mood | D．how cats are treated around the world |
| A．find out where the cats live | B．understand the cats’ lifestyle |
| C．build up the human-cat relationship | D．make up a dictionary of cat sounds |
| A．the owners’ voice plays a key role in the way cats meow |
| B．the research could bring about the cats’ welfare changes in shelters, for instance |
| C．the owners understand entirely the cats’ need through their meows |
| D．domestic cats live a happier life than wild ones |
| A．Optimistic. | B．Pessimistic. |
| C．Unconcerned. | D．Skeptical. |
China’s e-commerce enterprise Alibaba Group Holding Ltd aims to expand its reach across borders by upgrading its upcoming Nov 11, 2014 shopping festival into a global online shopping carnival.
“Globalization” is one of Alibaba’s main strategies for this year’s double 11 online shopping festival, which falls on Nov 11 every year. The online shopping festival last year was China’s largest and ended with two of Alibaba’s marketplaces Taobao and Tmall ringing up 35 billion yuan ($5.75 billion) in sales over the 24-hour period.
Wang Yulei, president of Alibaba’s business-to-customer site Tmall, said that this year’s Nov 11 shopping festival is going to be the group’s first shopping event that covers shoppers on a global scale. He said that Alibaba has for the first time set up servers overseas, which is expected to enable a rapid and smooth cross-border shopping experience on the day with a large number of people visiting the Tmall site. What is more, the e-commerce group has also set up warehouses overseas and strengthened cooperation with overseas logistics (物流) firms and customs authorities.“More than 200 overseas merchants from more than 20 countries have confirmed participation in this year’s ‘double 11’ event,” Wang said.
It is too early to tell whether the sales volume of Alibaba on Nov 11 will go up this year due to its global strategy. Wang from Tmall refused to reveal the sales target, only saying that sales at this year’s event will no doubt exceed last year’s. Insiders and analysts have different opinions on sales projections for the 24-hour online event ranging between 40 billion yuan to 100 billion yuan. Neil Flynn, head analyst at Shanghai-based Chineseinvestors.com, a leading financial analysis firm of US-listed Chinese companies, said Alibaba’s sales last year of 35 billion yuan was a 83 percent increase from the level recorded in 2012. “I would be looking for a minimum of 50 billion yuan in sales for this year’s Nov 11 festival,” he said.
Wang Xiaoxing, an analyst with the Beijing-based Internet consultancy Analysys International, said there would be a significant growth in this year’s sales, but the growth rate is likely to be less than last year’s 83 percent. “The projection is in line with the slowing growth tendency of the overall online shopping market in China,” he said.
“As Alibaba’s chairman Jack Ma wants the group to hit the long-run target of 100 billion yuan in sales, they can’t rely on Chinese consumers spending more and more each year on the same products. They need to expand their product range, which will increase the average purchase value in China, and they need to expand their customer base,” said Flynn.
“This (global Nov 11 shopping festival) also provides a great way for Alibaba to establish themselves on a global scale. It remains a China focused firm, but if it offers significant. discounts to consumers abroad, then they can expand their reach across borders,” he said. Wang from Analysys International said that Alibaba may be a familiar name for Western shoppers after the group’s IPO (首次公开募股), but there is still a long way to go for the group to compete in matured Western markets with strong local competitors. Flynn also has doubts as to whether Alibaba can compete with its American counterparts at this moment. “Tmall and Amazon provide very similar services, and Western customers have been using Amazon for years,” he said.
1. In preparation for its expansion to overseas markets, Alibaba did important things except ________.| A．establish overseas warehouses |
| B．build servers in foreign countries |
| C．appeal to foreign governments to attract customers. |
| D．improve cooperative relationship with distribution companies |
| A．Alibaba’s sales of 2012 was 83% of that of 2013. |
| B．Alibaba’s sales target of 2014 was 100 billion yuan. |
| C．Alibaba’s sales of 2013 was no less than 35 billion yuan. |
| D．Alibaba’s sales of 2014 would reach no more than 50 billion yuan. |
| A．Alibaba is known to every western household. |
| B．Alibaba will still center on Chinese domestic market. |
| C．Alibaba has imposed a big threat on western enterprises. |
| D．Tmall will provide a brand new experience for western shoppers. |
| A．Alibaba set to expand “double 11”. |
| B．Jack Mar’s dream of transforming Alibaba. |
| C．Taobao and Tmall, Alibaba’s effective weapon. |
| D．The battle of “double 11” is just around the corner. |
【推荐2】A shark attacked a 14-year-old girl near a Florida beach on Saturday, though a surfer tried to save her. The surfer pulled the girl from bloody water and frightened the shark away with his fists（拳头）.
Can sharks really smell blood in the water? Yes. Sharks have a good sense of smell, and blood happens to be a very attractive smell. Sharks also use sight and hearing to discover their food. In particular, hungry sharks like to hear the sounds which are made by swimming fish. They also look for something bright. Attacks on people can sometimes be a case of mistaken recognition. Sometimes, a shark could confuse shining stones for food.
The sharks’ eyes, ears, and nose are all near their mouth. But sharks also search for their food with sensory receptors（感受器）. These receptors can feel any movement in the water. When a shark gets very close to a food, it can use electroreceptive organs（电觉器官）, which sit the wall of little holes on the shark’s nose. Living things in salty seawater produce a weak electrical field（电磁场）that the shark can feel at a short distance, so it allows the shark to find out creatures that bury themselves in the sea floor. Muscle（肌肉）movements also produce little electrical fields that a shark can feel.
The surfer who tried to save the girl said he protected himself by frightening away the shark with his fists. Is that a good idea? Some experts think frightening away a shark with fists should only be the last choice. It won’t be wise for you to stay still in water. Swimming away rapidly seems to be a better choice. If you can’t swim away right away, hit the shark on the face or nose—where it has a high concentration of sensory receptors like humans—to drive off your attacker and give you enough time to escape. When you are beside a shark’s face, try sticking your finger in its eyes.
1. Which of the following helps sharks search for food?| A．Swimming quietly. | B．A special kind of blood. |
| C．Working as a team. | D．A good sense of smell. |
| A．Sharks can feel movements from other creatures in seawater. |
| B．Sharks use sensory receptor more than smell to search for food. |
| C．Sharks can’t feel weak muscle movements from other creatures. |
| D．Sharks can’t find and attack creatures hiding in the sea floor. |
| A．Shout loudly and frighten it away. | B．Get away from it immediately. |
| C．Touch the shark’s face gently. | D．Stay still to pretend to be dead. |
| A．Environment. | B．Sport. | C．Science. | D．Health. |
【推荐3】Have you ever bought a new car and started noticing the exact color and model of car everywhere? Has that type of car just become popular in your city? Were they there before? Or are you just going crazy?
You’re not going crazy. The reason you are now just noticing them is what psychologists call “priming”. Basically, the cars were always there. You just didn’t recognize them consciously. However, when that certain model of car becomes part of your conscious thinking, you start “automatically” recognizing all of the other cars that are the same, because you are already “primed” to do so.
The priming effect takes many forms. In one study, students were asked to walk around a room for 5 minutes at a rate of 30 steps per minute, which was about one-third their normal pace. After this brief experience, the participants were much quicker to recognize words related to old age, such as forgetful, old, and lonely. Reciprocal priming effects tend to produce a coherent reaction: if you are primed to think of old age, you would tend to act old, and acting old would reinforce the thought of old age. This research shows that the way we think influences the way we act, and the way we act influences the way we think.
A similar conclusion was reached by the American psychologist William James a century ago, but he emphasized the effect on feeling. “Actions seem to follow feeling, but really actions and feeling go together; and by regulating the action, which is under the more direct control of the will, we can indirectly regulate the feeling, which is not. Thus the path to cheerfulness, should our cheerfulness be lost, is to sit up cheerfully and to act and speak as if cheerfulness were already there.”
So, that’s it. If you want to be happy, just sit up and act happy. Based on these scientific findings, we can adopt certain priming effects to help make ourselves consistently happier.
One thing we have in common is our ability to think, and thus feel. Pleasant thoughts have been proven to produce the chemicals that make us feel happy, particularly thoughts and feelings of gratitude. When we purposefully go through and think about the things we’re grateful for and deliberately feel as much gratitude as we can, we are flooding our mind with the “happy chemicals”. Furthermore, by consciously thinking, feeling and expressing gratitude, we will not only be happier in the moment, we will be “primed” to recognize the things in our life to appreciate. Each time this happens, the “happy chemicals” will be produced. Do this every day and we will become consistently happier. This makes up for the momentary happiness we gain from eating chocolate or buying new clothes. More than that, combining thoughts of gratitude with happy acts like smiling and laughing will have a supplementary positive effect on our state of mind.
1. Which of the following is an example of the priming effect?| A．Walking much faster after attending a lecture about old age. |
| B．Donating money to the poor after seeing pictures of cute cats. |
| C．Learning about various types of cars after purchasing the first car. |
| D．Completing SO_P as SOUP rather than SOAP after seeing the word EAT. |
| A．Related. | B．Two-way. | C．Well-rounded. | D．Opposite. |
| A．Eating or shopping leads to consistent feelings of happiness. |
| B．Our will has greater control over emotions than over actions. |
| C．Happy chemicals make us think about the things we’re grateful for. |
| D．Practicing gratitude frequently prepares us for long-term happiness. |
| A．Prime Yourself to Be Happier |
| B．Share Happiness to Enhance Wellbeing |
| C．Why Gratitude Is Important in Psychology |
| D．How Happy Chemicals Affect People’s Thoughts |
【推荐1】It was an autumn day, and 1 was standing in the kitchen, hanging my head over the counter and trying to figure out how many calories were in a bowl of homemade yogurt and fruit. And I felt annoyed.
I was 16, and my best friend and I had gone to our first Weight Watchers meeting. It was the trend in the mid-1980s，and even though I was an athlete, like many teen girls, I didn't necessarily like what I saw in the mirror. But after a week or so of recording every meal and snack and calculating the calories, I had had enough. I went back to my routine of chowing whatever I wanted, running and skiing, and let that be that. And it's still pretty much what I do; as long as the workouts are regular and the food is whole and balanced, my body's set point hasn't varied for years.
The weight loss trend of three decades ago−full of scales and counting calories−has fallen away. Now fasting is popular. The ways to keep fit vary: on the 5:2 diet a person eats for five days and fasts for two days each week, while the 18:6 refers 10 fasting for 18 hours and then eating within a six-hour window each day.
In this issue, Associate Editor Mark Barna tries to understand the science behind the fasting plans. Researchers have found that animals like monkeys age more slowly after years of eating less, and in the lab in humans, they saw improvements in a number of signs that indicate risk of some hard to cure diseases. The hope for healthy weight loss isn’t over yet, but at least now the calculators don’t have to be out at every meal.
1. What made the author annoyed?| A．Her body was not as strong as an athlete’s. |
| B．There were too many calories in the yogurt and fruit. |
| C．The Weight Watches meeting was not necessary for her. |
| D．She had to work out the calories in every meal and snack. |
| A．Eating. | B．Doing | C．Cooking. | D．Choosing. |
| A．They limit the calories they take in. |
| B．They lose weight only. |
| C．They fast daily or weekly. |
| D．They eat enough every day. |
| A．People grow more slowly if they eat less. |
| B．People are healthier if they eat less. |
| C．People have stopped losing weight now. |
| D．People calculate their food for every meal. |
【推荐2】Scientists have created a scent(气味)-delivery system that releases a pleasant fragrance when you sweat. Apply it to your skin, and the more you sweat, the better you’ll smell. That’s because the perfume only gets released upon contact with moisture(湿气).
Chemists from Harvard University combined two compounds(化合物) to create their new system. One chemical is alcohol-based. This is the nice-smelling perfume. The other chemical is an ionic liquid(离子性液体), which is a type of salt that is liquid at room temperature. Ionic liquids are made of ions---molecules that have lost or gained one or more electrons. If the molecule loses electrons, it will have a positive charge. If it gains electrons, it gets a negative charge. Ionic liquids contain the same number of positive and negative ions, which makes them neutral(中性的), with no overall electric charge. In general, ionic liquids have no smell.
When the perfume and ionic liquid are mixed together, a chemical reaction occurs. This bonds the molecules to each other. The reaction also temporarily inactivates(使不活跃) the perfume’s molecules. So when applied to the skin, the new perfume has no scent in the beginning. But adding water or sweat breaks the bond between the molecules. That releases the scent into the air.
“The rate of the release of the fragrance depends on how much you sweat, in other words, how much water is available,” explains chemist Nimal Gunaratne from Harvard University, who led the research. “Sweat is like the command to let the fragrance go.”
Christian Quellet is a chemist who has worked in the perfume industry for a long time. He is now an independent consultant based in Switzerland. “Gunaratne’s perfume opens the door to new developments and applications of fragrance controlled-release systems,” he says. Controlled-release systems allow small quantities of some compounds that they hold to enter the environment slowly.
The system also traps some chemicals in sweat that are responsible for the bad sweat smell. These compounds are called thiols (硫醇). Just as water does, thiols break apart the bond that ties the perfume to the ionic liquid. When this happens, the thiols attach to the ionic liquid and their bad scent is inactivated as the perfume had been. This means the water in sweat and its thiols are both able to release the fragrance from the newly developed perfume.
1. Which of the following makes the scent delivery system special?| A．When it releases scent can be well controlled. |
| B．No perfume is required in the system. |
| C．The scent can last for a long time. |
| D．Sweat can help release the scent. |
| A．the perfume comes into contact with the skin |
| B．the perfume and ionic liquid contact each other |
| C．the perfume’s molecules are inactivated by water |
| D．sweat activates the molecules of the perfume in the mixture |
| A．the more you sweat, the better you will smell |
| B．the perfume can’t always cover the bad smell. |
| C．how much water is available doesn’t matter much |
| D．how you smell depends on how much perfume you use |
| A．Indifferent. | B．Favorable. | C．Doubtful. | D．Critical. |
【推荐3】Binge-watching(疯狂观看) your favourite TV series is bad for your brain, a neurologist has warned. Dr Randall Wright, based in Texas, said the need to watch episode(一集) after episode has a similar effect on the brain to gambling. What’s more, Dr Wright added that sitting in front of the screen for hours creates an ’unhealthy environment’.
The past time often leads to social isolation(孤立), snacking on junk food and a lack of exercise and sleep, which, over time, is bad for the brain, he said. But he said it is possible to get rid of the side effects of being a couch potato with four tips.
When you let auto play start the next episode so you can find out what happens next, your brain receives positive feedback, Dr Wright wrote in an article for the Houston Methodist Hospital. This instant satisfaction is similar to gambling(赌博), where even after a win, you are not satisfied and want to continue playing. With binge-watching, you are not satisfied with stopping after episode five and want to continue watching. This cycle coupled with the snacking can lead to unhealthy changes in your brain and body over time. Dr Wright said:“Binge-watching itself is not bad. It becomes problematic when watching a third, fourth or fifth episode replaces healthy activities.”
Dr Wright suggested exercising before a binge-watching TV – or even inbetween episodes – because activity helps the brain generate new cells. Setting an alarm can be helpful for reminding yourself to go to sleep at a decent time. Spending too much time in isolation can lead to depression, Dr Wright said, so it’s important to balance TV viewing with socializing. As for the snacks, Dr Wright advises to stay away from salty, fatty, calorific foods. Research has shown unhealthy eating while binge-watching can lead to piling on the pounds.
1. Which is NOT the bad effects caused by Binge-watching?| A．Eating junk food. | B．Doing little exercise. |
| C．More social communication. | D．Not having enough sleep. |
| A．Binge-watching itself is bad. |
| B．Binge-watching is similar to gambling in some way. |
| C．You are content with watching episode after episode. |
| D．It is unlikely to get rid of the bad effects of Binge-watching. |
| A．Keeping away from snacks matters. |
| B．We should balance TV viewing with socializing. |
| C．It gives suggestions about dealing with binge-watching TV. |
| D．Setting an alarm reminds yourself to go to bed on time. |
| A．Saying no to gambling. |
| B．Sitting for long is harmful. |
| C．Binge-watching, Bad for brain. |
| D．TV series have bad influences on your brain. |
