3 . The scientists who re-engineered the plastic-eating enzyme(酶) PETase have now created a new enzyme called “cocktail” , which can digest plastic up to six times faster.

PETase breaks down PET back into its building blocks, creating an opportunity to recycle plastic and reduce plastic pollution. PET is the most common thermoplastic(热塑性塑料) used to make single-use drinks bottles, which takes hundreds of years to break down in the environment, but PETase can shorten this time to days. The initial discovery set up the prospect of a revolution in plastic recycling, creating a potential low-energy solution to tackle plastic waste.

Now, the same trans-Atlantic team have combined PETase and its “partner”, a second enzyme called MHETase, to generate much bigger improvements: simply mixing PETase with MHETase doubled the speed of PET breakdown, and engineering a connection between the two enzymes to create a “super-enzyme”, increased this activity by a further three times.

The team was co-led by the scientists who engineered PETase, Professor John McGeehan and Dr Gregg Beckham. Professor McGeehan said: “Gregg and I were chatting about how PETase attacks the surface of the plastics and MHETase chops things up further, so it seemed natural to see if we could use them together. Our first experiments showed that they did work better together, so we decided to physically link them. It took a great deal of work, but it was worth the effort — we were delighted to see that our new enzyme is up to three times faster than the separate enzymes.”

The original PETase enzyme discovery indicated the first hope that a solution to the global plastic pollution problem might be within grasp, though PETase alone is not yet fast enough to handle the tons of PET bottles. Combining it with a second enzyme, and finding together they work even faster, means another leap forward has been taken towards finding a solution to plastic waste. PETase and the new combined MHETase-PETase both work by digesting PET plastic. This allows for plastics to be made and reused endlessly, reducing our reliance on fossil(化石) resources.

1. What can we learn about “cocktail” from the text?

A．It doubles the breakdown of plastics.

B．It takes hundreds of years to break down.

C．It contributes to breaking down plastic quickly.

D．It deals with the plastic waste three times faster.

2. What is the second paragraph mainly about?

A．A new study of PET.	B．The breakdown of PET.
C．The discovery of PETase.	D．The functions of PETase.

3. What does the underlined word “It” in Paragraph 4 refer to?

A．Co-leading the trans-Atlantic team.	B．Combining PETase and MHETase.
C．Attacking the surface of the plastics.	D．Talking about conducting experiments.

4. What can we infer from the text?

A．PET pollution is no longer a difficult problem to deal with.

B．New enzyme is speeding up our reliance on fossil resources.

C．MHETase-PETase makes the world free from plastic pollution.

D．Plastic-eating enzyme “cocktail” promises new hope for plastic waste.

4 . It’s been less than a month since Arnold, a Texas high school student, was forbidden from going to the prom and graduation unless he cut his locs. As his story spread on social media, celebrities and activists came to Arnold’s defence and encouraged him to stand up to his school’s hair discrimination. Now, in a significant turn of events, he’s proudly wearing his own hair-style at the 2020 Oscars.

Arnold and his mother were invited to attend as the guests of director Matthew A. Cherry, who won the award for Best Animated Short Film for Hair Love tonight. Fittingly, the short film tells the story of a Black father learning to style his daughter’s natural hair.

Arnold told us he couldn’t wait to walk the red carpet with the Hair Love team. “I’m so grateful. I never expected any of this,” Arnold says. “The message of that movie and my message go together so well. I think it’s really amazing how they reached out to me and how we can fight this together.”

Together, Cherry and Arnold are advocating for the nationwide passage of The CROWN Act, which is the law authored by California Senator Holly J. Mitchell that makes it illegal to discriminate against Black people for wearing their natural hair in the workplace or at school. Currently the Act has only been passed in New Jersey, California, and New York.

Arnold has also received the support of celebrities, including Ellen DeGeneres, who invited him to appear on her daytime show and surprised him with a $20,000 scholarship from Alicia Keys. Arnold says the scholarship will help him pursue his dream of becoming a veterinarian. Arnold tells us. “The most exciting thing is seeing all the people that are on my side. I thought it would be a lot more hate than support.” Tonight, Arnold is looking forward to sharing his story on a massive platform. “As teenagers, we have a voice and we’re the future,” he says. “I want more cultural acceptance. If there’s any other situation that I feel like I need to stand up for, I would do that in a heartbeat.”

1. What happened to Arnold not long ago?

A．He played a role in a short film.

B．He managed to apply for a scholarship.

C．He dropped out of school owing to his hair.

D．He was not allowed to attend some school activities.

2. What does the underlined word “this” in Paragraph 3 probably mean?

A．Violence.

B．Discrimination.

C．Panic.

D．Starvation.

3. What do we know from the passage?

A．Hair Love was based on Arnold’s experiences.

B．Alicia Keys shaped Arnold’s cultural acceptance.

C．Mitchell had been punished for wearing natural hair.

D．The CROWN Act has not been adopted nationwide.

4. What’s the writer’s main purpose in writing this passage?

A．To share a teenager’s story.	B．To advocate the passage of an act.
C．To introduce an Oscar-winning film.	D．To express his dissatisfaction with society.

5 . You might be the apple of your mother’s eye, which could only be a good thing. But adults who believe they are their mother's favorite child are at an increasing risk of depression, according to a study.

“It is a huge cost for those who think they get closest to their mothers, and these children report higher depressive symptoms（症状）,” said Professor Jill Suitor from Purdue University in Indiana, who led the study.

The academics used date collected from 725 adult children with an average age of 49, analyzing levels of emotional closeness, conflict, pride and disappointment.

The researchers added that previous studies had found that those who were closer to their mothers experienced less closeness with their siblings (兄弟姐妹).

Though few mothers or fathers would admit that they have a favorite son or daughter, studies have suggested they often do.

One such piece of research, which was carried out by the University of California in 2005, found that 65 percent of mothers and 70 percent of fathers showed a preference for one of their children over their siblings.

A previous study carried out by Professor Suitor and Dr Gilligan found that mothers tended to favor an adult child who was similar to them, in terms of values and beliefs.

Arabella Russell, a professor in Dorking, Surrey, said family problems, such as the siblings cannot get along well with each other, can often spill over into our romantic relationships, by influencing how we relate to our partners.

1. What does the underlined word “It” refer to in the second paragraph?

A．More chances to suffer from depression.

B．More time spent staying with their mothers.

C．More money spent on their growing up.

D．The disability to get along well with others.

2. Why do some mothers give more care to a certain child?

A．Because the child performs better.

B．Because they have similar attitudes.

C．Because the child is smarter.

D．Because they look similar.

3. What will happen if the family has a bad relationship?

A．The parents will be disliked.

B．The members will never make up again.

C．More members will have mental problems.

D．The children may have problems in their romantic relationships when growing up.

4. Who is the passage mainly written for?

A．The children.	B．Parents
C．The researchers.	D．The adult children.

6 . After watching the 2002 Winter Olympic Games on TV at 3 years old, Little Nathan Chen became interested in winter sports. Nathan wanted to play ice hockey (冰上曲棍球)，but his mom advised him to try figure skating(花样滑冰)first which she said was safer. After practicing a few times, Nathan fell in love with it.

Today, Nathan is influenced by all the athletes he meets. From the difficulties the athletes have faced and how they dealt with them, Nathan learns to work on dealing with his own difficulties as well. He describes all the athletes he trains with as role models for himself.

Nathan won gold at the 2017 ISU Grand Prix Final and 2017 Four Continents Championships, and silver at the 2016 ISU Grand Prix Final. Nathan has also broken a record, becoming the youngest man to win a medal at the 2017 U.S. Figure Skating Championships.

However, this journey has not come without hard times. Nathan suffered a bad injury during the 2016 season and it took him quite a long time to be able to compete again. At the beginning of the 2018 Olympics, Nathan was expected to win gold but got 5th place in the end. Nathan later described the race as “just me being on the ice and enjoying myself”, free from all the pressures. What matters the most isn’t the results, but the great memories you get from the experience and the joy of being able to do something you love.

This fall, Nathan will be attending Yale University and work on managing his time as a student and athlete. Aside from figure skating, Nathan would like to learn how to box. Besides, he plans to learn biology and later become a doctor.

1. What does the underlined word “it” in Paragraph 1 refer to?

A．Ice hockey.	B．Safe practice.
C．Figure skating.	D．The 2002 Winter Olympics.

2. What happened to Nathan Chen in 2016?

A．He was seriously injured.

B．He was accepted by Yale University.

C．He won gold at the ISU Grand Prix Final.

D．He won silver at the Four Cintinents Championship.

3. How did Nathan feel when he failed to win gold at the 2018 Olympics?

A．He felt very sad about the failure.

B．He felt the need to become better.

C．He couldn’t believe what had happened.

D．He didn’t care too much about the results.

4. What does Nathna hope to do after university?

A．Do boxing.	B．Play ice hockey.
C．Be a doctor.	D．Continue figure skating.

7 . You are with me once in a while for nearly 20 years now. You never said why you chose me. I didn’t even think I was your type. I had always thought you went for the worrier, the unadventurous. But I am an outgoing girl. Maybe you were impressed with my demanding teaching career. Your past lovers come from all walks of life. I see them yell and accuse under your pressure.

I often keep you a secret. I refuse to let my identity be swept up in yours. Besides, sometimes when people talk about you, what they are concerned is how they know you, too and the ways to be relaxed and get away from anxiety. But you and they are only casual acquaintances—the intensity (强度) is incomparable.

I am writing now because I have noticed that we are growing apart. So there are things I want to say. I know my daily exercising annoys you; you’re nowhere to be seen when I’m reading our favourite books. I’ve noticed that you’re turned off by the way I’m eating fruits and vegetables. When I take the time to chat with a stranger or a friend, you often storm off. So I’ve decided it is time to start making plans of my own, despite not knowing what yours are.

I know we will always be in touch. You’ll visit me when I least expect it. But plan on being prepared. If we do eventually split for good, you should know you have changed me for the better. Because of you, I see that life is a fragile gift to be handled with awakened care and patience. So learn to keep you at bay by getting away from stress.

In short, appreciate you for what you have brought into my life but I ask you to give me the distance I need to live the lessons you have taught.

1. The word “you” mentioned in the passage refers to ________.

A．a secret	B．a bad feeling
C．a teacher	D．the author’s best friend

2. Which activity of the author will “you” like?

A．Reading her favorite books.	B．Chatting with her friends happily.
C．Working out on regular basis.	D．Doing demanding work and feeling stressed.

3. What’s the author’s attitude towards “you”?

A．She is grateful to “you”.	B．She has pity on “you”.
C．She can’t forgive “you”.	D．She regrets treating “you” badly.

4. Where is the passage probably taken from?

A．A poem.

B．A guidebook.

C．A diary.

D．A biography.

8 . In recent decades，countries around the world have made great progress against malaria．However a new report from the World Health Organization（WHO）says that progress is at risk．

This WHO annual report looks at the global fight against the disease．It says that malaria cases are on the rise in several countries．

Many countries are moving toward eliminating malaria，among them Madagascar，Senegal and Zimbabwe．However，the WHO report warns that in others，progress has stalled．

Malaria cases increased by more than 20 percent from 2015 to 2016 in eight African countries﹣including Rwanda，Nigeria and the Democratic Republic of Congo．
At the same time，funding for malaria prevention and treatment has leveled off，reaching﹩2.7 billion in 2016．This amount is less than half of the 2020 target．

Professor David Conway is from the London School of Hygiene and Tropical Medicine．He says money for fighting malaria has plateaued，meaning it has not increased in a long time．

Overall，Africa continues to suffer the most from malaria．In 2016，just over 400，000 people died from the disease．This is slightly less than in 2015.However，in Africa the malaria parasite does not yet appear to be developing drug resistance．

The same cannot be said for Southeast Asia．

Conway explains that there are renewed concerns that in Southeast Asia malaria will become drug﹣resistant in the future．

The WHO is calling for improving the coverage of existing methods of malaria prevention as well as an urgent investment in new tools﹣﹣namely a malaria vaccine．

Professor Conway said，"More research is needed to develop an effective malaria vaccine that could cover the populations that at the moment have high malaria rates and that perhaps don't use the available interventions even when they are being funded．"

Several malaria vaccines are under development．Starting in 2018，the WHO is planning a major trial of the RTSS vaccine in Kenya，Ghana and Malawi．

But this latest report from the WHO warns that the world is at a crossroads．Without better funding and more effective tools to fight malaria，the progress made in recent decades could be undone．

1. Which of the following statements is not true？

A．A bit more than 400，000 people died from malaria in African countries．

B．More and more money has been put in malaria prevention and treatment．

C．Fewer and fewer people are suffering from malaria in the past decade．

D．Malaria cases decreased less than 20 percent in eight African countries in 2016．

2. What does the word"they"in Paragraph 3 from the bottom mean？

A．malaria

B．the available interventions

C．the populations

D．malaria rates

3. Why does the WHO show the worry about the battle of anti﹣malaria nowadays？

A．Progress of fighting malaria is greatly short of money and effective tools．

B．More and more people cannot get treatment for malaria in time．

C．No countries are likely to have got funding and effective tools from the WHO．

D．Some malaria sufferers in Africa have refused to get treatments from the WHO．

9 . Climate change leads to a threat to the world’s sandy beaches, and as many as half of them could disappear by 2100, a new study has found. Even by 2050 some coastlines could be unrecognizable from what we see today, with 10% to 12% facing severe erosion (侵蚀).

Using updated sea level rise predictions, the researchers analyzed how beaches around the world would be in a future with higher seas and more damaging storms. They also considered natural processes like wave erosion, as well as human factors-like coastal building developments, all of which can affect a beach’s health. The study found that sea level rise is expected to outweigh these other factors, and that the more heat-trapping gases humans put into the atmosphere, the worse the influences on the world’s beaches are likely to be.

It’s hard to overstate just how important the world’s beaches are. They cover more than one third of the world’s coastlines, and protect coastal areas from storms. Beaches are also important economic engines, supporting relaxation, tourism and other activities. And in some areas, the beach is more than a vacation destination. In places like Australia, life near the coast revolves around the beach for much of the year.

Some of the world’s most popular beaches are already taking action. Places like Miami Beach are trucking in thousands of tons of sand to patch up (修复) badly eroded shorelines, while others have built sea walls and breakwaters in an attempt to hold precious sand in place. But the financial and environmental costs of these projects are huge, and scientists say rising seas and more powerful storms, supercharged by a warmer climate, will make this a losing battle.

However, the researchers did find that humans have some control over what happens to the world’s beaches. If the world’s governments are able to stick to modest cuts to heat-trapping gas pollution, the researchers found that 22%of projected beach losses by 2050 could be prevented, a number that grows to 40%by 2100 if greenhouse gases are limited.

1. Which is the biggest contributor to severe beach erosion?

A．Damaging storms.	B．Wave erosion.
C．Coastal building.	D．Sea level rise.

2. What can we infer from Paragraph 3?

A．It is hard to protect coastal beaches.

B．One third of storms take place near beaches.

C．Beaches are of great significance to our lives.

D．Most Australians live on beach tourism.

3. What does the underlined word “this” refer to in Paragraph 4?

A．Popularizing the beaches.

B．Holding sand in place.

C．Reducing the project costs.

D．Stopping global warming.

4. What is the best title for the text?

A．Half beaches could disappear by 2100.

B．Climate change is doing harm to our lives.

C．The beach is more than a vacation destination.

D．Governments are taking action to fight wave erosion.

10 . Have you imagined that planting trees can make a big difference? People say that one man can’t make a difference, but Abdul Samad Sheikh, a 60-year-old rickshaw (人力车) driver from Bangladesh, has proved that doing a small thing over a long period of time can mean very much. He has planted at least one tree every day since he was 12 years old, which means that he has so far planted a small forest of over 17,500 trees. Imagine if everyone followed his example.

Abdul has worked as a rickshaw driver for most of his life. He makes a little money from his job, which is only enough to put food on the table for his family, but he somehow tries to also buy at least one tree every day. He considers it his duty to the world. Mostly he plants them on government land so nobody can cut them down later. He also waters them, and if he sees anyone cutting a tree, he blames them.

Abdul, his wife Jorna, and four of their children live in two old houses, on a piece of land that is owned by the Faridpur deputy commissioner’s office. They have no land of their own.

Sometimes, she commands him not to plant trees but he doesn’t listen. Abdul’s 30-year-old son, Kutub Uddin, has never told his father not to plant trees, because he thinks his father does a good thing for society.

Abdul’s neighbors all know about his daily habit, and praise his work. Whoever can ask of him anything, he will do his best to help. Therefore, Abdul is loved by neighbors.

For his efforts, Abdul Samad Sheikh was recently honored by The Daily Star, and given $1,253 to help him build a better home for his family. The Daily Star wished everyone to follow his example, and protect the environment.

“I can’t do it alone. I need the help of you all,” Abdul said in his speech.

1. What do we know about Abdul?

A．He doesn’t support his family.	B．He plants trees with his own money.
C．He makes a living by doing different jobs.	D．He plants trees to win his neighbors’ praise.

2. Why does Abdul plant trees on government land?

A．To get money from government.

B．To set a good example to people.

C．To protect them from being cut down.

D．To get a place from government to build his own house.

3. Which of the following can best describe Abdul?

A．Poor but helpful.	B．Rich and reliable.
C．Uncaring and stupid.	D．Active but dishonest.

4. What does the underlined word “it” in the last paragraph refer to?

A．Driving a rickshaw.	B．Planting trees.
C．Making big money.	D．Building a better home.