1 . Sometimes, you just can’t say no to another spoonful of ice cream and maybe one more after that. Why not? You deserve it.
There’s no need to beat yourself up about it later. The truth is that you were probably bound to do that from the very first spoonful. That’s because there is a switch in your brain, and for whatever reason, it can get stuck in the “on” position.
According to a new study, this impulse (冲动) control may come down to a very specific circuit (回答) in the brain which occasionally produces melanin-concentrating hormone, or MCH—a chemical linked with our desire for food or drugs. And that circuit always says yes.
By manipulating this circuit, it is possible that we might be able to develop cures for overeating that help people stick to a diet without reducing normal appetite or making delicious foods like donuts less delicious.
For their research, the scientists treated rats to a self-serve buffet. Bur the treats were on a timed delivery system, making tasty food every 20 seconds, and only when a rat pressed a lever (杠杆). Hit that lever too early—as impatient test subjects occasionally did—and the counter would start from scratch. Lever-happy rats would have to wait another cycle before the food became available again.
A second experiment offered the rats two dining options. Push Lever A and get an immediate small reward. Pushing Lever B meants waiting for around40 seconds, but the food reward would be much bigger. Guess which lever those impatient rats were most food of? That’s right. They picked the now-now-now switch.
Their impulsiveness, however, rose sharply when scientists gave the rats MCH. These animals become more impulsive. MCH, it seemed, could talk rats into loosening its inhibitions (拘束). The result? More please.
Researchers can now see where that conversation between the brain’s reward system and its impulse control center takes place. The next step will be to map it—and potentially influence the discussion. It may eventually be possible to control a food-eating impulse.
1. Which of the following can best replace the underlined word “manipulating” in paragraph 4?| A．Strengthening. | B．Controlling. |
| C．Classifying. | D．Creating. |
| A．A bigger food reward would appear. |
| B．Tasty food would be delivered much sooner. |
| C．Longer time would be needed for food to appear. |
| D．The lever would be stopped form delivering food. |
| A．To find out the effect of MCH on animals. |
| B．To prove rats are also greedy for more food. |
| C．To study how levers influence rats’ impulse. |
| D．To show rats and humans have similar impulse for food. |
| A．What Is the Effect of Your Impulse? |
| B．What Can You Do to Resist More Food? |
| C．Why Can’t You Say “No” to Your Impulse? |
| D．Why Do You Always Give in to One More Mouthful? |
2 . Chinese restaurants began to open in America in the mid-19th century, mainly on the west coast where the first immigrants landed. They mostly served an Americanized version of Cantonese cuisine, chop suey, egg fu yung and the like. In that century and much of the 20th,the immigrants largely came from China's south-east, mainly Guangdong province.
After the immigration reforms of 1965, Chinese migrants from other regions started to arrive. Restaurants began calling their food "Hunan” and “Sichuan". Though their food rarely resembled what was actually eaten in those regions, it was more diverse and boldly spiced than the sweet, fried stuff that defined the earliest Chinese menus. By the 1990s adventurous diners in cities with sizeable Chinese populations could choose from a variety of regional cuisines. A particular favorite was Sichuan food, with its addictively numbing fire due to peppercorn.
Yet over the decades, as Chinese food became universal, it also came to be standardized. There are almost three times as many Chinese restaurants in America (41,000)as McDonald's. Virtually every small town has one. And generally the menus are consistent: pork dumplings （steamed or fried);the same two soups(hot and sour, wonton);stir-fries listed by main ingredient, with a pepper icon or star indicating a slight trace of chilli-flakes. Dishes over$10 are grouped under "chef's specials".
Until recently, the prices varied as little as the menus and they were low. Eddie Huang, a Taiwanese-American restaurateur, recalls how his newly-arrived father kept his prices down because" immigrants can't sell anything full-price in America."
Americans have traditionally been willing to pay through the nose at French or Italian joints （where, in fact, Latinos often do most of the cooking).And every city has its pricey sushi bars and expensive tapas restaurants(tapas, as one joke goes, is Spanish for"$96 and still hungry").
Mr. Huang is right that Americans have long expected Chinese food to be cheap and filling. One step up from the urban takeaway, with its fluorescent lighting, is the Chinese restaurant with its red doors and fake lions standing guard, exotic enough to be special, but still affordable enough for a family to visit once a week when nobody feels like cooking. Even the superior outlets were cheap for what they served.
But now things are changing. Mr. Huang sells delicious stuffed buns in New York and Los Angeles for$5.50 each and encourages other immigrants not to undervalue their work.
Meanwhile, although racism persists, the previous discrimination of earlier ages has been fading. Since the Chinese-American population is six times what was 40 years ago, Americans overall are much more familiar with Chinese people and their cooking, all of which means that the new fancy breed of Chinese restaurants draws a heartening mix of Chinese and non-Chinese diners.
1. We can learn from the first three paragraphs that_| A．Cantonese cuisine was well received by Americans in the 19th century |
| B．Those so-called Hunan or Sichuan food in America tasted just as what was actually eaten in those regions |
| C．Nowadays Chinese restaurants are almost twice more than McDonald's in America |
| D．Americans prefer Hunan food because they have been addicted to peppercorn |
| A．Americans have long expected Chinese food to be cheap and filling. |
| B．Earlier immigrants couldn't sell anything full-price in America. |
| C．Americans prefer French and Italian food. |
| D．Chinese restaurants face fierce price competition from other restaurants. |
| A．In order of importance. |
| B．In order of place. |
| C．In order of time. |
| D．In order of position. |
| A．Immigration on a plate. |
| B．Americans' favourite cuisine. |
| C．Prejudice against Chinese immigrants. |
| D．Route to success. |
3 . Humans really do have a sixth sense that lets us detect magnetic fields (磁场), but we’re not aware we have it. It has long been known as ESP, Spider Sense, or the ability to see things before they happen. But now scientists have proved that humans really do have a sixth sense-that lets them detect magnetic fields. Tests have shown that mankind may have the same inborn sense of Earth’s magnetic field that has long been proved to exist in animals.
By putting a protein from the human retina (视网膜) into fruit flies, researchers noticed that the insect adjusted its flight path just as if its eye had not been changed. This suggests that the “sixth sense” does exist in humans but we might not be aware of it. Animals use such sight to navigate long distances during migration or, in the case of birds, to “see” where they are going. The complex tests involved examining the process by which light goes through a bird’s eye, which has interested the scientific community for more than 30 years. In the late 1970s, the physicist Klaus Schulten concluded that birds fly by relying on geomagnetically (地磁) sensitive biochemical reactions in their eyes.
Tests have shown that the special cells in the eye carry out this function using the protein cryptochrome (蛋白隐色素). Professor Reppert’s team used wild fruit flies, replacing their version of cryptochrome with the human equivalent (等价物), and then put them in a maze (迷宫) with each wing wrapped in a metal coil (金属圈). They then sent electricity through it so that the coil was magnetised in a way which is just like Earth’s electromagnetic field (电磁场). The flies responded in exactly the same way as if they had their own cryptochrome, by either avoiding the magnetic fields or moving towards them if the researchers had placed sugar nearby.
The new study was published in the journal Nature Communications.
1. What do we know about humans’ sixth sense?| A．Humans have been aware of it since ancient times. |
| B．It is quite different from the animals’. |
| C．It is the ability to predict what will happen. |
| D．It is also a sense developed after birth. |
| A．To change fruit flies’ flight path. |
| B．To test if humans have a sixth sense. |
| C．To examine the process of birds’ flying. |
| D．To allow researchers detect magnetic fields. |
| A．the maze | B．each wing |
| C．cryptochrome | D．the metal coil |
| A．They responded normally as if there had been nothing changed. |
| B．They couldn’t avoid the magnetic fields like before. |
| C．They lost the sense of direction completely. |
| D．They couldn’t find the sugar the researchers had placed nearby. |
4 . Most of Earth’s freshwater sits underground. Worldwide, about 70 percent of the groundwater drawn to the surface goes for farming. But surface waters — rivers and streams — come from groundwater, too. Drawing too much groundwater over a short time can be harmful. Natural waterways can begin to empty. And that can hurt freshwater ecosystems. Scientists consider this a tipping point when small actions can begin making unusually big differences.
A new study has found that 15 to 21 percent of tapped water (自来水) areas have reached this sort of tipping point. Most of those tapped rivers and streams are in dry areas. Farmers in these areas use groundwater to water their crops. At present drawing rates, the study predicts that 42 to 79 percent of water areas around the world where groundwater is drawn up for use at the surface will reach tipping points by 2050.
A healthy groundwater aquifer (含水层) protects ecosystems against seasonal ups and downs in the use of water. That provides stability for area plants and animals. But if too much groundwater is drawn up from below, surface waters will begin to flow into the aquifer, which can harm what are living in rivers and streams.
De Graaf and the study team set up a computer model. It linked groundwater drawing and water flows within rivers. The model covered fifty years, from 1960 to 2010. Then the researchers used climate forecasts to help the model predict what might happen in future years. Throughout, they kept groundwater drawing rates sustainable. More than half of drawn water areas are likely to cross this ecological tipping point before 2050, the model finds.
“We need to be thinking about this now, not in 10 years,” De Graaf says. “Our study shows us where to target more sustainable efforts.”
1. What does the “tipping point” in paragraph 1 mean?| A．End point. | B．Breaking point. |
| C．Freezing point. | D．Boiling point. |
| A．Warn us that the surface water can pollute the groundwater. |
| B．Warn us of watering the crop by groundwater. |
| C．Tell us the relation of groundwater and surface water. |
| D．Warn us that the overuse of groundwater can destroy the ecosystem. |
| A．Keeping the stability of natural water. |
| B．Protecting ecosystems from pollution. |
| C．Clearing surface waters to be drinkable. |
| D．Providing stability for the local economy. |
| A．They predicted the result based on the old data. |
| B．They happened to work out the result. |
| C．They measured all the groundwater and surface water. |
| D．They did questionnaire surveys on the water information. |
5 . Over a million children have developed some form of intellectual （智力） disability over the past two decades after being exposed to chemicals including flame retardants, pesticides, lead, and mercury, a study has revealed.
The study focused on the four chemicals, which can be crossed from a mother to her unborn baby through the placenta（胎盘）and cause neurodevelopmental damage. The researchers looked at data from past studies, including blood samples taken from women of childbearing age and 5-year-olds.
Over the period, flame retardants, resulted in 738,860 cases of intellectual disability and an estimated 162 million lost IQ （智商）points, followed by lead at 330,684 cases, pesticides at 111,830, and mercury at 8,860. In recent years, pesticides and flame retardants have overtaken lead and mercury as the chemicals responsible for the biggest loss of IQ among children.
The researchers believe this is due to regulations cutting down the use of these chemicals. For instance, lead has been banned from gasoline, paint and drinking water systems in the U.S. and plants are not allowed to pump out mercury.
The researchers acknowledged limitations to their study, including that the exposure-response relationships might not relate to all populations. Positively, they found a huge drop in the estimated loss of IQ points among children.
Lead researcher Abigail Gaylord, commented: "Our findings suggest that our efforts to reduce exposure to heavy metals are paying off, but that harmful exposures in general continue to represent a terrible risk to people's physical, mental, and economic health. "Unfortunately, the minimal policies in place to remove pesticides and flame retardants are clearly not enough," she said.
She also added. Frequently opening windows to let persistent chemicals found in furniture electronics, and carpeting escape, and eating certified organic produce can educe exposure to these harmful things"
1. Which contributes most to the loss of children's IQ?| A．Flame retardants. | B．Pesticide. |
| C．Lead. | D．Mercury. |
| A．A school report. | B．A science fiction. |
| C．A scientific research. | D．A chemistry book. |
| A．It has received bad response from all populations. |
| B．It has no previous information to refer to. |
| C．It covers only part of the population. |
| D．It is not supported by government policies. |
| A．Four chemicals harming children. |
| B．Regulations cutting down the use of heavy metals. |
| C．Environment risking people's physical and mental health. |
| D．Children IQ lowered by exposure to harmful chemicals. |
6 . A new study focuses on K2-18b, an exoplanet (系外行星) like the earth discovered in 2015, orbiting a red dwarf star (矮星) close enough to receive about the same amount of radiation from its star as the earth does from the sun.
Recently, scientists have discovered gas giants that have water in their atmospheres, but this is the least massive planet ever to have water detected in its atmosphere. ''The water detection was quite clear to us relatively early on, lead author Bjorn Benneke, a professor at the Institute for Research on Exoplanets at the Universite de Montreal, '' told Space.com in an interview.
Studies have suggested that planets with hydrogen-rich atmospheres could host certain forms of life, Benneke said. However, a news release reads: ''K2-18b's large atmosphere is extremely thick and creates high-pressure conditions, which likely prevents life as we know it from existing on the planet’s surface. '' While these researchers found evidence for liquid water clouds on K2-18b because of its lack of surface, rain wouldn't pour on the planet. Without a real surface, so to speak, landing on the planet would also be nearly impossible, especially because the gas is so thick and has such an incredibly high pressure that any earthr-created space-craft sent there would be devastated.
Benneke suggests that, possibly, this planet is formed by rock absorbing large amounts of gas, like a vacuum (真空) cleaner. This absorbed gas would have more than doubled the planet and increased its volume eightfold.
To come to these conclusions, the research team analyzed the data from Hubble Space Telescope observations that they made between 2016 and 2017 of the K2-18b planet passing in front of its star eight times. It allows scientists to detect distinct characters of water in a planet's atmosphere. This team plans to expand this research even further by studying K2-18b with NASA's James Webb Space Telescope, which is set to launch in 2021. This type of research, Benneke said, is leading toward a final goal of ''being able to study the earth-like planets. '' ''We are not quite there yet. '' he said, ''but this is really exciting. ''
1. What can we learn about K2-18b?| A．It is a planet closest to the sun. |
| B．It hosts certain forms of life because of thick gas. |
| C．It is covered with thin atmosphere and liquid water. |
| D．It's the smallest planet with water in its atmosphere ever found. |
| A．Declared. | B．Detected. |
| C．Destroyed. | D．Delivered. |
| A．The expansion in the research. |
| B．The data by the Hubble Space Telescope. |
| C．The goal of recognizing the real exoplanet. |
| D．The conclusion of increasing the planet's volume. |
| A．A New Finding About K2-18b |
| B．NASA Helps Explore An Exoplanet |
| C．Humans Have Ever Landed On K2-18b |
| D．Scientists Determination Of Researching Space |
7 . Fireworks have been enjoyed by countless people ever since they were invented in China during the Tang Dynasty hundreds of years ago. From small family gatherings (团聚) to huge global celebrations, there isn’t a party that couldn’t be made more fun with a few fireworks. But it seems that there’s a big price to pay for some brief beauty and fun.
It’s been discovered that fireworks contain metals such as copper (铜) and lead, in addition to other pollutants like perchlorates (高氯酸盐). According to the Environmental Protection Agency, perchlorates can form naturally or be made. They are an industrial chemical used in rocket fuel and explosives (炸药), and are soluble (可溶解的) in water.
This is a reason for concern because perchlorates negatively affect the thyroid gland (甲状腺), which influences important bodily functions like blood pressure and heart rate.
Furthermore, a study conducted by Terry Gordon, a professor at New York University, examined the emissions(排放物) whose sizes were big enough to enter the lungs. They concluded that these emissions may lead to various dangerous conditions like cancer, heart attacks, and strokes (中风).
It is worth noticing, however, that no studies have proven the connctions between these conditions and the dangerous chemicals in fireworks.
However, the negative effects of firework emissions can be observed in birds. Britain’s Royal Society for the Protection of Birds warns against setting off fireworks close to wildlife areas as they may cause confusion among birds.
In 2010, an incident involving 5,000 red-winged blackbirds falling out of the sky on New Year’s Eve in Arkansas, US supported this idea. A fireworks display held at a nesting ground for blackbirds led to the birds’ night sight being affected, causing them to fall to their deaths.
Arguably (可以说), the use of fireworks during celebrations may be because people don’t realize how they pollute our environment. Companies and researchers could take this cue (线索) and find other new, eco-friendly ways.
After all, for all the beauty fireworks bring, there’s no better beauty than that of our planet’s.
1. According to the article, perchlorates contained in fireworks ______.| A．do harm to the thyroid gland |
| B．raise the risk of cancer |
| C．are dangerous when put in water |
| D．are made from copper and lead |
| A．fireworks are directly connected with lung cancer |
| B．the waste from fireworks could threaten our body |
| C．chemicals in fireworks could increase our blood pressure |
| D．our body is strong enough to fight against the pollutants in fireworks |
| A．Positive. | B．Negative. |
| C．Indifferent. | D．Neutral. |
8 . It’s often said that the rise of social media has revolutionized (彻底改变) communication. With smartphones and social networking apps, we can write to our family and friends whenever we like. But while social media has brought us convenience, it also has its problems, such as misunderstandings in communication.
Quite often, people misunderstand what’s written on social media. According to a story published on The Conversation on March 8, sarcasm (讽刺), in particular, can be very difficult to notice in a written message.
Sarcasm is a kind of irony (反语): It’s when we say something, but really mean the opposite. For example, a message from a friend the day before a math exam that says “I’m so looking forward to tomorrow!” is obviously sarcasm.
Sarcasm before the rise of social media and mobile phones was mostly used in speech and face to face. That made sarcasm easier, because you could accompany your words with a facial gesture and a tone (语气) of voice that would help others get your message. You had a good chance of being understood and receiving a laugh or an understanding glance.
And yet when we text or write something online, a lot of that information goes missing. “There are no facial hints, no tones or maybe even a delayed response if a person can’t text you back immediately,” wrote The Conversation. “And if you don’t know the person all that well, there goes your last possible hint: history.”
To help avoid misunderstandings, people who use platforms such as Twitter often include the hashtag ﹟sarcasm – although this is like having to explain a joke when people don’t laugh at it, which destroys the point of sarcasm in the first place.
And it isn’t only sarcasm that can get lost in electronic communications. It’s also hard to notice things such as indifference (冷漠).
“One of the problems with digital communication, when it relies purely on text, is that this sucks (抽离) the empathy (情感共鸣) out of the communication. So it can lead to miscommunication,” linguist Vyv Evans, author of The Emoji Code, told USA Today. “This is where emojis come into their own. They put the body language back, so people can better read emotional intent (目的).”
However, even though there are hundreds of different emojis(表情符号) to choose from, there’s still no replacement for good old-fashioned face-to-face communication.
1. What does the underlined sentence in the third paragraph mean according to the context?| A．They can’t wait to take the exam. |
| B．They are well-prepared for the exam. |
| C．They’re not looking forward to taking the exam at all. |
| D．The exam might be too difficult for them. |
| A．The use of new internet words and phrases. |
| B．The complicated relationship between people. |
| C．The absence of facial expressions and tones. |
| D．Responding to other people too quickly. |
| A．Using emojis, as they can display body language. |
| B．Expressing fewer personal feelings. |
| C．Sending voice messages instead of text messages. |
| D．Using a hashtag before making jokes. |
| A．The convenience of online communication. |
| B．Some misunderstandings that come with digital communication. |
| C．A good replacement for face-to-face communication. |
| D．Some reasons for the popularity of emojis. |
9 . Slang(俚语) is very informal language which is often used by young people. It’s hard to keep up to date with it as new words and phrases appear and evolve (发展). Living in a multicultural society has an effect on language, especially on the young, whose friends are often from a mix of backgrounds. TV and music also have a big impact. A complete list of slang is difficult to make; by the time it was finished, the list would be out of date. However, here are a few examples:
Safe, sorted, sound, cool or wicked all mean “That’s good” or “I understand”.
Instead of using different tag questions (附加疑问句) like “… isn’t it?”, “… can’t you?” or “… don’t they?”, people use “innit”.
For example, “He can dance really well, innit!” (= He can dance really well, can’t he?) or “They always say that, innit.” (= They always say that, don’t they?)
Instead of saying “very”, “really” or “completely” use “well”, for example, “I’m well tired” or “You got it well wrong!”
“Whatever” means “I don’t care”, for example, A: “But the teacher says we can’t leave until we’ve finished.” B: “Whatever. I’m going.”
“He’s fine” or “he’s fit” both mean “He’s good-looking”. Fine and fit can describe a boy or a girl.
Not everybody uses slang and not everybody likes it. A school in the north of England recently told its pupils to stop using slang words such as “hiya” (hello), “cheers” and “ta” (both mean “thank you”) if they wanted to get a place at university or a good job.
When British people use language like this, it’s no surprise that some say they can’t understand native speakers. But perhaps learners don’t need to worry so much. Research shows that most of the English spoken around the world today is between non-native speakers of the language.
So, how important is it to understand these slang words and expressions? If you watch films or TV in English, read magazines in English, chat online in English or are interested in English song lyrics, then understanding slang can be very useful. You probably won’t see much slang in your English examination, though.
1. Why is it hard to make a complete list of slang, according to the article?| A．Because many slang words are outdated. |
| B．Because it is mostly used by young people. |
| C．Because modern slang changes very quickly. |
| D．Because it comes from different cultural backgrounds. |
| A．It prevents language from evolving. |
| B．It is also spread through TV and music. |
| C．It is more popular in the UK than in the US. |
| D．It has found its way into formal written English. |
| A．Knowing little slang doesn’t greatly affect how one communicates. |
| B．Many UK schools are encouraging students to use slang. |
| C．It is essential for English learners to study some British slang. |
| D．More English is spoken by native speakers than by non-native speakers. |
10 . When Denis wants to relax at work, he steps into a quiet room, sits in a chair, slips on a virtual-reality headset, and escapes to the beach. For Denis, those minutes are a tool he relies on regularly to both relieve and prevent stress.
He's not the only one at his company to use the room, where workers can also use a headset to watch a moon walk, take a virtual roller-coaster ride or access a meditation (冥想) app.
Research shows VR can help reduce pain and anxiety. But it's not yet clear why it works. Experts believe it's related to the technology's power to distract.
''Whatever their problems are, whatever their stresses are, they can literally neglect them and have a different emotional pulse, '' Denis said.
Virtual-reality headsets haven't taken off with consumers, but they're now powerful and inexpensive enough for companies to consider investing in them to help make workers and customers happier.
The headsets may help people take a virtual break from their surroundings, but there are challenges to consider. Ramon Llamas, a tech market researcher, noted that there could be challenges in handing out headsets. Some people get sick or dizzy while using virtual reality, and the headsets may get dirty or broken. There's also the task of quickly familiarizing people with using the headsets, especially since VR adoption has been so limited and the ways they are controlled can vary.
For now, Llamas said, he's concerned about privacy and security. What if, for instance, someone manages to back into a headset and insert some content into what you're watching?
Another potential issue is the managing of the headsets and software that goes along with them. This is likely not a complication for an office like Umber Realty's, where people can simply take a headset off if they feel something wrong. But it could be more of a problem if you're stuck in a dentist's chair. ''The last thing you want is that in the middle of extracting a tooth something goes wrong.'' Llamas said.
1. What does Denis's company use Virtual Reality for?| A．Improving the customers' experience. |
| B．Displaying the schedule of his company. |
| C．Relieving the staff's work pressure. |
| D．Saving the trouble of transportation. |
| A．Ignoring reality for the moment. | B．Improving their thinking. |
| C．Designing work for the company. | D．Investing in a new industry. |
| A．The potential problems with VR. |
| B．The privacy policy available for VR. |
| C．The management of these devices in the market. |
| D．The standards the VR technology is to follow. |
| A．VR, a promising business in future! | B．Is VR always making us relax? |
| C．The adoption of VR needs investments. | D．Are we saying ''goodbye'' to VR? |
