Energy goes from one plant or animal to another. A food chain shows how this energy moves. Each time an animal gets eaten, its energy is passed onto the animal that eats it. The food chain is very important because it keeps the balance of nature. If one part of the food chain disappears, it can affect all the other plants and animals. Any threat to the food chain is a threat to the environment’s biodiversit(生物多样性). The food chain helps keep animal populations in balance. However, if something happens to increase or decrease one of the links in the food chain, that balance is broken. If one animal becomes endangered, it puts all the animals above it at risk.
Some of the threats are natural, such as wildfires, hurricanes, tornados, floods and so on. But the biggest threats to the food chain come from you and me. These threats include overhunting, overfishing, logging, farming, development, pollution, etc. The food chain is endangered anywhere humans have had an effect on the natural environment.
A recent study shows that the overfishing of large sharks is damaging the food chain along the US Atlantic coast. Canadian and American scientists say sharks are being killed in great numbers for their meat and fins(鳍). Now, not enough sharks are around to eat the cownose(牛鼻) ray. The ray’s population has increased and they have eaten up the shellfish to the point where it has hurt commercial(商业的) fishing.
Many of us disturb the natural environment in our own backyards. It’s up to us to take care of the environment and try not to disrupt the natural food chain. If we don’t act responsibly, animals will start disappearing.
1. What can we learn from Paragraph 1?

A．The food chain is not easy to be broken.

B．The energy of an animal usually disappears when it dies.

C．Increasing the links will not break the balance of nature.

D．Breaking the food chain is bad for the biodiversity of the environment.

2. The study mentioned in Paragraph 3 proves that            .

A．human activities can be a big threat to the food chain

B．we are all responsible for the breaking of the food chain

C．natural disasters are hard to break the food chain

D．hunting large sharks for meat is beneficial

3. We can infer that the writer wrote this passage mainly to           .

A．explain what the food chain is

B．tell us something interesting about Nature

C．suggest that we stop eating meat to save animals

D．suggest that we not disrupt the natural food chain

One day, I received a call from a colleague. He was about to give a student a zero for his answer to a physical problem, while the student claimed a perfect score. I was elected as their arbiter (仲裁人). I read the examination problem: “Show how it is possible to determine the height of a tall building with the aid of a barometer (气压计).” The student had answered, “Take the barometer to the top of the building, attach a long rope to it, lower it to the street, and then bring it up, measuring the length of the rope. The length of it is the height of the building.”

The student had really answered the question completely, but the answer didn’t confirm his competence in physics. I suggested the student try again. I gave him six minutes to answer the question, warning that the answer should show some knowledge of physics. Five minutes later, he said he had many answers and dashed off one, which read “Take the barometer to the top of the building and lean over the edge of the roof. Drop the barometer, timing its fall with a stopwatch. Then, use the physical formula (公式) to calculate the height of the building.”

At this point, my colleague had to accept it, and then the student made almost full marks. I couldn’t help asking the student what the other answers were. He listed many others and then added, “Probably the best is to take the barometer to the administrator and said to him, ‘Sir, here is a fine barometer. If you tell me the height of the building, 1 will give it to you.”‘

Then, I asked the student if he really did not know the conventional answer to this question. He admitted that he did, but said that he was fed up with high school and college instructors trying to teach him how to think.

The name of the student was Bohr who later was famous all over the world. He won the Nobel Prize for Physics in 1922.

4. The student got a zero at the beginning because       .

A．the teacher wasn’t satisfied with him.

B．his answer wasn’t complete or correct

C．his answer didn’t show his knowledge of physics

D．the teacher didn’t fully understand his answer

5. We know from the passage that       .

A．the administrator told Bohr the height

B．the student knew the expected answer

C．the author preferred Bohr’s last answer

D．the teacher was a very stubborn person

6. We can learn from the passage that       .

A．instructors can teach students how to think

B．arbiters can help students to get high scores

C．teachers should make students use physical formulas

D．students should be given more freedom in thinking

7. What was Bohr’s attitude toward his schooling?

A．Critical	B．Optimistic
C．Objective	D．Ambiguous

One in five people carry a “smart gene” variant (变体) linked to long lifespan, bigger forebrains and enhanced mental ability, researchers have found.

“We’ve known for a long time that people lose cognitive (认知) abilities as they age, but now we’re beginning to understand that factors like KLOTHO can give people a boost in aging. Genetic variation in KLOTHO could help us predict brain health and find ways to protect people from the diseases that happen to us as we grow old, like Alzheimer’s disease (老年痴呆症),” said senior author, Dena Dubal of University of California.

The KLOTHO gene affects a protein found in the kidneys and the brain that regulates many different body processes. About one in five people carry a single copy of the variant, known as KL-VS, which boosts levels of the protein and is associated with a longer lifespan and improved heart and kidney function. A small minority, 3% of the population, has two copies, which is linked to a shorter lifespan.

In the new study scientists scanned the brains of 422 men and women aged 53 and over who were also tested for the KLOTHO gene. They found that participants with a single copy of the gene variant also had a larger brain region known as RDLPFC, which is especially likely to shrink with age. Loss of neurons in this area may be one reason why older people are sometimes easily distracted and find it difficult to do more than one task at the same time.

Researcher Dr Jennifer Yokoyama said, “The brain region enhanced by genetic variation in KLOTHO is vulnerable (脆弱的) in aging and some mental disease. In this case, bigger size means better function. It will be important to determine whether the structure increase associated with carrying one copy of KL-VS can offset the cognitive shortage caused by disease.”

People who have one copy of a variant KL-VS tend to live longer and have lower chances of suffering a stroke (中风),whereas people who have two copies may live shorter lives and have a higher risk of stroke.

8. What can we learn from the second paragraph?

A．People’s cognitive abilities do not decline if people have KLOTHO.

B．With the clear understanding of KLOTHO, Alzheimer’s disease can be cured now.

C．Genetic variation in KLOTHO could be helpful in treating mental disease in elderly people.

D．Genetic variation in KLOTHO could lead people to suffer from Alzheimer’s disease.

9. If a person carries two copies of the gene variant, he/she may _______.

A．have better kidney funtciton

B．have a shorter lifespan

C．have a higher level of the protein in his/her body

D．suffer from some cognitive disease

10. The reason why older people’s attention is easily distracted may be that _______.

A．they have fewer neurons in the RDLPEC

B．their brain region is too large

C．they have two copies of the gene variant

D．they have more neurons in the RDLPEC

11. What does the underlined word “offset” in Paragraph 5 probably mean?

A．Prevent.

B．Balance.

C．Keep.

D．Promote.

Alibaba started taking the lead in China by connecting big Chinese manufacturers(制造商) with big buyers across the world. Its business-to-business site, Alibaba.com allowed business to buy almost everything. Alibaba’s advantage wasn’t hard to judge: size. Alibaba is just big, even by Chinese standards. Its market attracts 231 million active buyers, 8 million sellers, 11.3 billion orders a year — and Alibaba is just the middleman. It encourages people to use its markets — not charging small sellers a percentage of the sale.
If you want a quick look into the influence of Alibaba on daily Chinese life, take my experience. I moved to Beijing a year ago and quickly got tired of visiting small stores across the crowded, polluted city of 20 million people in search of new electronics, bathroom furnishings, and anything else my wife wanted. “You’re looking for what exactly? Why not try it? ” my Chinese teacher asked me one day. With that, my wonderful new relationship with Alibaba began.
Alibaba’s original business-to-business model now is second to consumer buying. Chinese retail(零售) buying makes up 80% of Alibaba’s profit, and leading that group is Taobao, with 800 million items for sale and the most unbelievable selection of things you’ll ever find. TMall.com is Alibaba’s other big site, where you can find brand name goods from Nike and Unilever near the lowest prices.
What I have a hard time explaining to friends and family back in the U.S. is how China has gone beyond traditional shopping — big-box retailers especially —in favor of online purchases on Taobao and a few other sites. In smaller towns than Beijing, where big retailers have not yet traveled, shopping online is shopping, and shopping is Taobao.
I have a list of some of my recent purchases on Taobao for a sense of how wide the marketplace is. Almost everything arrived a day or two after ordering with free shipping. I’m not even a big buyer, because I need friends to help me search the Chinese-language site. When I was searching my purchase history on my Chinese teacher’s iPad, which helps me buy goods, I looked through with great difficulty about 10 of her purchases for every one of mine.
12. Alibaba’s advantage mainly lies in          .

A．its low price

B．its big size

C．its not charging small sellers

D．its business-to-business service

13. We know from the passage that Alibaba         .

A．will continue to develop.

B．charges all the sellers on its site a percentage of the sale.

C．acts as a bridge between the buyers and sellers.

D．is of middle size among all the online sites.

14. What can be inferred from the passage?

A．Alibaba’s business-to-business service earns more money than retail.

B．TMall.com provides more profit than Taobao.

C．Taobao has no obvious advantage over other similar online sites.

D．The author’s Chinese teacher is also an online purchase lover.

15. What is the passage mainly about?

A．Shopping online in China is TaoBao.

B．How the author purchases online in China.

C．Shopping online goes beyond traditional shopping.

D．Alibaba influences people’s daily purchase in China.

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中的两项为多余选项。
        We’d better develop our interest in English at the beginning of our study.    16    We may feel good when we can say something simple in English.

    17    So we must make some plans before study.And we should certainly carry out these plans in our study.

    18    Our notes are much thinner than the books so that we can learn them by heart easily and can often review and read them.We may also record our notes on tapes so as to listen to them easily.
        Reading a newspaper is the best thing to improve your English.    19    It will help you keep in touch with a lot of subjects in English.

    20    Learn by heart the whole sentences and the phrases that contain the new words so that we may know how to use the words.If time permits,we may read a mini Chinese-English dictionary carefully from cover to cover,which may help us widen our sight and master knowledge in all ways.

A．Read a little from a newspaper every day.

B．Don’t read books without making notes.

C．Carefully write an e-mail in English.

D．It’s easy to develop an interest in English study.

E．The more,the better.

F．Plans are always very necessary.

G．Never just memorize single English words.