1 . Why did humans evolve to walk upright? Perhaps because it’s just plain easier. Make that “energetically less costly,” in science-speak.
Bipedalism — walking on two feet — is one of the defining characteristics of being human, and scientists have debated for years how it came about. In the latest attempt to find an explanation, researchers trained five chimpanzees to walk on treadmill while wearing masks that allowed measurement of their oxygen consumption. The chimps were measured both while walking upright and while moving on their legs and knuckles. That measurement of the energy needed to move round was compared with similar tests on humans and the results are published in this week’s online edition of Proceedings of the National Academy of Sciences.
It turns out that humans walking on two legs use only one quarter of the energy that chimpanzees use while knuckle-walking on four limbs. And the chimps, on average, use as much energy using two legs as they did when they used all four limbs.
However, there were differences among chimpanzees in how much energy they used, and this difference corresponded to their different gaits and anatomy. One of the chimps used less energy on two legs, one used about the same and the others used more, said David Raichlen, assistant professor of anthropology at the University of Arizona.
“What we were surprised at was the variation,” he said in telephone interview. “That was pretty exciting, because when you talk about how evolution works, variation is the bottom line, without variation there is no evolution.”
Walking, on two legs freed our arms, opening the door to manipulating the world, Raichlen said. “We think about the evolution of bipedalism as one of first events that led hominids down the path to being human.”
The research was supported by the National Science Foundation and the L. S. B. Leakey Foundation.
1. The underlined word “Bipedalism” means .| A．moving sideways | B．walking upright |
| C．walking on four legs | D．running fast |
| A．Masks protect chimpanzees from any harm. |
| B．Masks help chimpanzees walk steadily. |
| C．There was heavy smoke in the room. |
| D．Masks helped to measure how much oxygen chimpanzees consumed. |
| A．have no idea on how human walking on two legs came about |
| B．have had different views on why chimpanzees walk on four legs |
| C．have had different views on how human walking on two legs came about |
| D．have had similar views on how human walking on two legs came about |
| A．How did chimpanzees save energy? | B．Why didn’t chimpanzees walk on two legs? |
| C．David Raichlen researched into chimpanzees. | D．Different chimpanzees consume different energy. |
| A．conserve energy | B．differ from other animals |
| C．free their brains | D．strengthen their legs |
2 . From talking robots and video phones to rovers (探测器) on Mars, technology has become so advanced that the previously impossible seems to occur on a daily basis. And yet—we still have no cure for the common cold.
Why can’t we stop the common cold? According to Peter Barlow, a scientist at Edinburgh Napier University in the UK, the main challenge lies in the many different types of cold viruses that are produced by the rhinoviruses (鼻病毒), Scientific American reported. There are at least 160 types. They mutate so easily that they quickly become resistant to drugs, or learn to hide from our immune systems. In other words, a single cure isn’t likely to work on every type of cold.
However, researchers from Stanford University and the University of California, San Francisco, have found a possible answer. They discovered a protein that the viruses need. Without it, they can’t spread inside your body.
To identify the gene which produces the specific protein needed by the viruses, researchers used a gene-editing technique to test all genes in the human genome (基因组) one by one for thousands of cell.
These modified cells were then exposed to a range of enteroviruses (肠道病毒), including the rhinoviruses which cause the common cold. All the viruses were unable to replicate inside cells without a gene that produces a specific protein, called methyltransferase (甲基转移酶) SETD3. Then, they tested genetically modified mice, which were completely unable to produce the protein. The mice were able to live healthy, normal lives without the protein. “Lacking that gene protected the mice completely from viral infection,” associate professor Jan Carette, from Stanford, told the BBC.” These mice would always die, but they survived and we saw a very strong reduction in viral replication and very strong protection. “Carette said the plan is to find a drug which can temporarily suppress the protein, instead of producing genetically modified humans.
“We have identified a fantastic target that all enteroviruses and rhinoviruses require and depend on. Take that away and the virus really has no chance,” said Carette. “This is a really good first step—the second step is to have a chemical that mimics this genetic deletion,” he added.
1. What does the underlined word ”mutate” mean in English?| A．To change a new form. |
| B．To identify a new gene. |
| C．To check a modified cell. |
| D．To cure a viral infection. |
| A．Why it is so hard to cure the common cold. |
| B．The possible link between rhinoviruses and the common cold. |
| C．A possible way to stop viral infections that cause the common cold. |
| D．The functions of a protein needed by viruses. |
| A．It helps the viruses replicate inside our bodies. |
| B．It allows the viruses to change easily. |
| C．It helps the viruses become resistant to drugs. |
| D．It increases the spread of the viruses. |
| A．Genetically modified mice died because they lacked the protein. |
| B．The modified cells seemed to protect the mice against viral infections. |
| C．More methyltransferase SETD3 was produced after the cells were modified. |
| D．The gene-editing technique was more effective against enteroviruses than rhinoviruses. |
| A．Conduct experiments on genetically modified humans. |
| B．Identify a drug that can help reduce the protein. |
| C．Apply this gene-editing technique to control other viruses. |
| D．Find a chemical that can cure all enteroviruses and rhinoviruses. |
3 . Want to have a better sleep? You may just need more noise. While that may sound strange, it’s scientifically proven that certain types of noise can help you get some sleep. Think of it this way: When you’re lying in bed, every single noise—from the creak of the bed to a whistle in your partner’s nose—may keep you awake. But some types of noise, specifically white, pink and Brown noise, can mask (掩饰) these sounds, creating a more harmonious background.
White noise contains sounds of all frequencies that humans can hear, but it comes across (使产生的……印象) as a high-pitched buzz (声调高的嗡嗡声). That’s because of the way your ears hear it. Basically, your brain strengthens sounds in higher pitch frequencies. So while you may be hearing sounds from a variety of frequencies, the highest ones tend to drown (淹没) the lower pitched notes.
Pink noise takes the human tendency to hear only some frequencies into account and balances out the noise so that sounds of all frequencies are heard equally The higher the frequency, the more its volume is weakened. To your ears, the sound is deeper and softer than white noise.
In a study at China’s Peking University, researchers found that when participants were exposed to either pink noise or no noise during nighttime sleep and naps, 75% reported more restful sleep with the pink noise. Brain activity monitors proved this, showing that participants had 23% more restful brain activity at night with pink noise and 45% more restful sleep during naps.
Brown noise takes this concept to the next level, further weakening higher frequency noise to produce an even deeper and richer sound. It’s not named after the color brown but rather after the botanist Robert Brown, who in the 1800s discovered random particle motion (随机粒子运动). Brown noise is similar to random particle motion for the changes in sound signals from one moment to the next happen randomly.
When it comes right down to it, the color of noise that will help you sleep most soundly is the one you like best. While pink noise and Brown noise are deeper and more balanced than white noise, your personal sleep preferences will dictate which one gives you the best sleep.
1. How can some noise help us have a better sleep?| A．By making us think of some special sounds. |
| B．By confusing our brain with different sounds. |
| C．By reducing the effects of disturbing sounds. |
| D．By copying the sounds that we are familiar with. |
| A．removes low-frequency sounds |
| B．protects ears from high-pitched sounds |
| C．makes sounds of all frequencies heard equally |
| D．contains sounds of all frequencies people can hear |
| A．Brown noise and pink noise work in a similar way. |
| B．Brown noise was first discovered by Robert Brown. |
| C．People cannot have a good sleep without pink noise. |
| D．People benefit more from pink noise at night than in the daytime. |
| A．Explain. | B．Control. |
| C．Reflect. | D．Decide. |
| A．Entertainment. | B．Education. |
| C．Science. | D．Travel. |
4 . When a dog looks at you with big puppy-dog eyes, it’s hard for you to go away, and you may speak out “Awww” without hesitation. However, there’s a reason why you find a dog’s stare so attractive. That sweet stare actually causes the release of a particular hormone, or chemical messenger in the body. This hormone creates feelings of affection in humans. The same thing happens to dogs when people look back at them. Scientists believe this helps people and their four-legged friends bond, or feel connected. Scientists have wondered what causes dogs to lovingly stare at their owners. To find out, a team of researchers from Azabu University in Japan studied 30 owners and their dogs.
The researchers found that after the pets and their owners spent half an hour together, both showed a rise in oxytocin (催产素). One key role of this hormone in many animals is to promote bonding, like that between a mother and newborn. The increase of oxytocin didn’t happen, though, when scientists repeated the experiment with wolves and the humans who had raised them.
A second experiment also found that if dogs were given oxytocin, they looked at their owners longer. Scientists aren’t sure exactly why, but this reaction occurred only with female dogs. Their owners’ oxytocin levels also rose as a result.
The result of these experiments might help answer an age-old question: How did the fearsome wolf ancestor of modern dogs turn into man’s best friend? Takefumi Kikusui, an animal scientist who worked on the study, thinks that the change happened when dogs first became domestic (驯养的).
According to Kikusui, there may have been a small group of wild dogs that were naturally friendlier. “Humans are very sensitive to eye contact. By using this special communication tool, the dogs are able to win over our hearts. If they are more likely to make eye contact, it would be easier for them to bond with dog owners,” Kikusui said.
1. According to Paragraph1, people say “Awww ” to ________.| A．make the dog stare at them | B．express their love for the dogs |
| C．draw the dogs’ attention away | D．warn the dogs not to approach them |
| A．reduce animals’ pain of giving birth |
| B．motivate animals’ desires to protect others |
| C．help animals to develop a better relationship |
| D．enable animals to survive more easily from dangers |
| A．dogs given oxytocin react differently |
| B．female dogs are more popular among humans |
| C．oxytocin helps dogs become man’s best friends |
| D．wolves are not likely to be friends with humans |
| A．dogs and wolves are best friends |
| B．wolves begin to bond with humans |
| C．dogs became friends with humans |
| D．dogs were domesticated by humans |
| A．To call on humans to be friendly to dogs. |
| B．To give advice on how to get along with dogs. |
| C．To introduce the evolution process of wild dogs. |
| D．To explain why humans and dogs are connected. |
5 . There are many things that influence whether someone has a quiet voice or a loud voice. Physical factors at work include the size of the person’s “voice box”, the amount of breath support the speaker provides and the size of the speaker’s lungs. Other factors such as the pitch of the voice (too high or too low) influence how well people’s voices are heard, particularly in a crowd.
Personality features are at work here, too. People who are not confident or who are fearful in social situations can find they speak more quietly than they wish they did. In your case, since people are always telling you to speak up, you may be anxious when you speak, which may cause you to become more murmurous.
There are several things that might help you. Professional people have lots of skills to improve the voice so that people with quiet voices can be heard more easily.
It also sounds as if “shyness” is something you see as a problem as well. It might be helpful to take a “confidence training” or “social skills” class to learn how to overcome some of the shyness. You might find that this “speaking too quietly” problem disappears when you feel more self-confident. Some actors report that they are shy people and that acting helps them overcome this anxiety. Acting coaches work with people to help them overcome their public shyness and they often are experts at helping people be heard loudly.
No matter how you decide to do it, we encourage you to ask for help with this worry. Learning to be confident and to be heard is very important. Becoming “confident” doesn’t mean that you will become “too loud.” It only means you will be able to express your views and receive others’ attention.
1. The first paragraph mainly tells us ________.| A．what the voice box is | B．which factors influence the voice |
| C．the lung influences the pitch | D．different people have different voices |
| A．seek help from Medical Doctors | B．change your personality features |
| C．try your best to become a good actor | D．learn some skills to improve your voice |
| A．it’s easy to build your confidence |
| B．it’s impossible for a shy girl to speak up |
| C．confidence can help you express your ideas |
| D．the louder you speak, the more confident you are |
| A．how to speak louder | B．that you should be confident |
| C．that you should always speak loud | D．why you have a low voice |
6 . From a very early age, some children exhibit better self-control than others. Now, a new study that began with about 1,000 children in New Zealand has tracked how a child's low self-control can predict poor health, money troubles and even a criminal record in their adult years.
Researchers have been studying this group of children for many years now. They observed the level of self-control the youngsters displayed. Parents, teachers, even the kids themselves, scored the youngsters on measures like “acting before thinking” and “Persistence in reaching goals.”
The study led by Moffitt of Duke University and colleagues followed 1, 000 children from birth to age 32 in Dunedin, New Zealand.
“The children who had the lowest self-control when they were age three to ten, later on had the most health problems in their 30s,” Moffitt said, “and they had the worst financial situation. They were more likely to have a criminal record and to be raising a child as a single parent on a very low income.” Moffitt explained that self-control problems were widely observed, and weren’t just a feature of a small group of misbehaving kids.
Moffitt said it's still unclear why some children have better self-control than others, though she said other researchers have found that it's mostly a learned-behavior, with relatively little genetic influence. But good self-control can be set to run in families because children with good self-control are more likely to grow up to be healthy and successful parents. But the good news, Moffitt said, is that self-control can be taught by parents, and through school education.
1. From the first two paragraphs we learn that________.| A．the research has been carried out for five years |
| B．self-control in kids probably determine their future |
| C．self- control was decided by children's intelligence |
| D．children's self-control is almost the same at early age |
| A．become wealthy in later life | B．get good school performance |
| C．have better financial planning | D．behave negatively |
| A．Self-control cannot be taught in schools. |
| B．The study is limited within few participants. |
| C．It's never too late to deal with self-control problems. |
| D．Good parenting can improve self-control and life success. |
7 . Calories are a way of keeping track of the body's energy budget. A healthy balance occurs when we put in about as much energy as we lose. If we consistently put more energy into our bodies than we bum, the excess will gradually be stored as fat in our cells, and well gain weight. If we bum off more energy than we replenish, well lose weight. But how many calories do we actually need? Calorie is just the unit we use to measure the energy we take in or bum.
Calories are used in three ways: about 10% enables digestion, about 20% fuels physical activity, and the biggest part, around 70%, supports the basic functions of our organs. That third usage corresponds to your basal metabolic rate (基础代谢率), a number of calories you would need to survive if you weren't eating or moving around.
According to the official guidelines, average person requires each day 2000 calories for women and 2500 for men. Those estimates are based on factors like average weight, physical activity and muscle mass. So does that mean everyone should take in around 2000 calories? Not necessarily. If you're doing an energy consuming activity, like cycling the Tour de France, your body could use up to 9000 calories per day Pregnancy requires slightly more calories than usual, and elderly people typically have a slower metabolic rate, energy is burned more gradually, so less is needed.
And one thing you should also know. The calorie counts on nutrition labels measure how much energy the food contains, not how much energy you can actually get out of it, Fibrous (纤维的) foods like celery and whole wheat take more energy to digest, so you'd actually absorb less energy from 100 calorie serving of celery than a 100 calorie serving of potato chips. Not to mention the fact that some foods offer nutrients like protein and vitamins, while others provide far less nutritional value. Eating too many of those foods could leave you overweight and malnourished. And even with the exact same food, different people might not get the same number of calories.
So a calorie is a useful energy measure, but to work out exactly how many of them each of us requires, we need to factor in things like exercise, food type, and our body's ability to process energy.
1. What is Calorie according to the passage?| A．A unit of measurement to the energy people get or consume. |
| B．The food people eat and digest. |
| C．The unit for people to count weight. |
| D．The way people to measure nutrition. |
| A．less food is eaten than before | B．doing exercise every day |
| C．more energy is fueled than taken in | D．one keeps energy balanced |
| A．The excess of calories will gradually turn into cells. |
| B．Most of the calories will help people with digestion. |
| C．When staying still no calorie will be needed. |
| D．The biggest amount of energy will go to support body organs. |
| A．potato chips are hard to digest |
| B．the food with more fibers can help keeping slim |
| C．the foods with protein and vitamins could leave you overweight and malnourished |
| D．old people's energy is gradually burning fast |
| A．Calories and Diet |
| B．Many Factors Contribute to Calorie Count |
| C．The Relevancy between Calorie Burning and Age |
| D．Different People, Different Calorie Burning Rate |
8 . The moon may shine white above us most nights of the year, but how much do we know about Earth’s neighbor and what lies beneath its surface? Scientists are aiming to find out.
On Jan 3, 2019, China’s Change 4 spacecraft landed on the far side of the moon a first for humanity. It released a small probe（探测器）,Yutu 2, or Jade Rabbit 2, which began to search beneath the moon’s surface using Lunar Penetrating Radar（探测雷达）. These radio signals can reach 40 meters underground, three times the depth of the Chang’e 3 lunar probe launched in 2013 for the near side of the moon, China Daily reported.
In a study published in the journal Science Advances, researchers found that the lunar soil’s top layer on the far side of the moon was much thicker than expected ﹣ about 40 meters. Other scientists only expected about 6 millimeters of soil based on NASA observations during the Apollo moon landings, according to The New York Times.
“It’s a fine, dusty, sandy environment, said one of the authors of the study, Elena Pettinelli, a physics and mathematics professor at Rome Tre University, Rome.
Yutu 2 is specifically exploring the Von Karman crater（大坑）,a large hole that’s 180kilometers wide and also the landing site of Chang’e 4. It’s part of an even larger, older crater spanning more than 1,770 kilometers.
“The subsurface at the Chang’e 4 landing site is very complex,” said Li Chunlai, a research professor and deputy director﹣general of National Astronomical Observatories of the Chinese Academy of Sciences. Observations suggest that the subsurface material is totally different than the previous landing site of Chang’e 3, she said.
Radar waves revealed various layers beneath the moon’s surface: grainy（ 颗粒状的）material, boulders（岩石）,and further layers of fine and coarse（粗糙的）particles. This information is helping scientists to gain new understanding of the moon’s history and formation, as well as volcanic activity and lunar impacts.
Yutu 2 is the longest﹣working rover（巡视器）on the moon, but it won’t last forever. China plans to launch the Chang’e 5 probe later this year, Xinhua News Agency reported. The spacecraft is expected to bring pieces of the moon back to Earth for closer study.
1. What can we learn about the Chang’e 4 probe?| A．It was the first to land on the moon’s near side. |
| B．It explored areas as wide as 1,770 kilometers. |
| C．Its signals could reach 40 meters beneath the moon’s surface. |
| D．It is three times as large as the Change 3 lunar probe. |
| A．It looks like a large hole. |
| B．It is about 6 millimeters thick. |
| C．It goes farther down than expected. |
| D．It is covered by boulders and fine and coarse particles. |
| A．It observed material beneath the moon’s surface which is helping scientists to know the moon better. |
| B．It has offered us relevant information on the near side of the moon. |
| C．It told scientists the landing site is very complex. |
| D．It revealed the surface material on the moon which is helpful to know the moon’s activity and impact. |
| A．Explore the Von Karman crater. |
| B．Replace Yutu 2 to explore the moon. |
| C．Identify the moon’s various layers. |
| D．Bring lunar samples back to the Earth. |
| A．A history of Chinese lunar missions. |
| B．How Yutu 2 explored beneath the moon’s surface. |
| C．report on the Chang’e 4 probe’s findings. |
| D．A comparison of the Change 3 and 4 probes. |
9 . Cause and effect is one way to explain things that happen around us. Many things happen because something caused or influenced them to happen. Sometimes it is hard to look at a cause and find out what causes the effect. It may help you to start with the effect and use your reasoning (推理的) skills. Think about all the things you know that could be reasons for the effect you can see.
For example，you may see someone putting on a heavy jacket. This is the effect. To look for a cause，think to yourself，“What would make someone put on a heavy jacket？”Maybe the person is going outside into very cold weather. Maybe the person works in the penguin pen (企鹅圈养地) at Sea World. Maybe the person is going to visit an ice skating rink where the air is kept very cold. All of these things could be a cause for putting on a heavy jacket.
Now，think about a second example. The effect is a boy named Abi has to go to the head teacher's office. What are the possible causes？Maybe he bullied (欺负) another student. Maybe he is just being picked up early. Maybe he is being given a prize!
Here is another example for you to think about its cause and effect. Cait，13，was trying to fall asleep when her 8yearold brother，Doug，came into her room. He looked around a bit，but seemed really out of it. Then Doug went back into the hallway(走廊) and stood there looking straight up at the hall light for quite a while. Little brothers can be very strange，but this was really much too strange. Cait didn't know what to do. Just then，Cait's father appeared and explained that Doug was sleepwalking. What's the cause and effect，could you tell?
1. According to the second paragraph，which of the following is an effect?| A．Someone puts on a heavy jacket. |
| B．Someone works in the penguin pen. |
| C．Someone will go outside into cold weather. |
| D．Someone will go to visit an ice skating rink. |
| A．He bullied another student. |
| B．He is going shopping. |
| C．he is being picked up early. |
| D．He is being given a prize. |
| A．He was going outside. |
| B．He was reading a story. |
| C．He was sleepwalking. |
| D．He was looking for his dad. |
| A．Tony got up and had a glass of water. |
| B．We came home and found him sleeping. |
| C．The ball was lost and a window was broken. |
| D．Tim was late again and his teacher got angry. |
| A．Truth and lies | B．Work and sleep |
| C．Cause and effect | D．Life and dreams |
10 . I read somewhere that we spend a full third of our lives waiting. But where are we doing all of this waiting, and what does it mean to an impatient society like ours? To understand the issue, let’s take a look at three types of “waits”.
The very purest form of waiting is the Watched-Pot Wait. It is without doubt the most annoying of all. Take filling up the kitchen sink(洗碗池) as an example. There is absolutely nothing you can do while this is going on but keep both eyes fixed on the sink until it’s full. During these waits, the brain slips away from the body and wanders about until the water runs over the edge of the counter and onto your socks. This kind of wait makes the waiter helpless and mindless.
A cousin to the Watched-Pot Wait is the Forced Wait. This one requires a bit of discipline. Properly preparing packaged noodle soup required a Forced Wait. Directions are very specific. “Bring three cups of water to boil, add mix, simmer three minutes, remove from heat, let stand five minutes.”I have my doubts that anyone has actually followed the procedures strictly. After all, Forced Waiting requires patience.
Perhaps the most powerful type of waiting is the Lucky-Break Wait. This type of wait is unusual in that it is for the most part voluntary. Unlike the Forced Wait, which is also voluntary, waiting for your lucky break does not necessarily mean that it will happen.
Turning one’s life into a waiting game requires faith and hope, and is strictly for the optimists among us. On the surface it seems as ridiculous as following the directions on soup mixes, but the Lucky-Break Wait well serves those who are willing to do it. As long as one doesn’t come to rely on it, wishing for a few good things to happen never hurts anybody.
We certainly do spend a good deal of our time waiting. The next time you’re standing at the sink waiting for it to fill while cooking noodle soup that you’ll have to eat until a large bag of cash falls out of the sky, don’t be desperate. You’re probably just as busy as the next guy.
1. While doing a Watched-Pot Wait, we tend to ___________.| A．keep ourselves busy |
| B．get absent-minded |
| C．grow anxious |
| D．stay focused |
| A．The Forced Wait requires some self-control. |
| B．The Forced Wait makes people passive. |
| C．The Watched-Pot Wait needs directions. |
| D．The Watched-Pot Wait engages body and brain. |
| A．It is less voluntary than the Forced Wait. |
| B．It doesn’t always bring the desired result. |
| C．It is more fruitful than the Forced Wait. |
| D．It doesn’t give people faith and hope. |
| A．Take it seriously. |
| B．Don’t rely on others. |
| C．Do something else. |
| D．Don’t lose heart. |
| A．exploring various causes of “waits”. |
| B．describing detailed processes of “waits”. |
| C．analyzing different categories of “waits” |
| D．revealing frustrating consequences of “waits” |
