4 . With low temperatures and food shortage, winter is a terrible season for animals. Many animals enter hibernation (冬眠) to get through it. Hibernation can help cool the animal’s body and slow its heartbeat to just a few times per minute, for up to months at a time.

But why don’t humans hibernate? Our body is not fit for hibernation. Humans have only migrated into temperate and subarctic areas (温带和北极地附近) in the last hundred thousand years or so. That’s not quite long enough to evolve (进化) all the metabolic adaptations (代谢适应) we would need to hibernate, according to the BBC Science Focus magazine. For example, how to settle waste is a big challenge for human hibernation. Animals that hibernate are able to stop their defecation (排泄), and sometimes save energy by taking their waste. Unluckily, humans can’t do this. There are other challenges. Body temperature below 2.8℃ may hurt human’s stomach and cause pain. Cold temperature can also make people ill easily, according to Smith-sonian magazine.

In fact, humans don’t need to sleep through winter. We can use fire, clothes, houses and food to help us live in the cold.

Could humans hibernate in the future? According to University of Oxford in the UK, being able to hibernate would make such long-time journey less boring and save important energy for the astronauts. It’s likely for long-term space travel. From 2014, NASA has worked hard to do a research on it, for it will be a way to help develop long-term space travel, according to The Atlantic magazine.

7 . Alaina is a shy French college girl. Last year, she came to Beijing, _____ capital of China, for the first time. As an exchange student, she didn’t know much about Chinese culture, _____ sometimes she didn’t know what she should do.

One day, she dropped in at her Chinese friend. When she arrived ____ her friend’s home, she was warmly welcomed. The host greeted her at the door. She _____ a cup of tea and she drank it up. Then when her cup was empty, the host would fill it up. In fact, Alaina was not so thirsty, but she didn’t know how _____ the host. After drinking ten cups of tea, she had to go to the toilet twice. And then the host found she behaved strangely and knew she had too _____ tea.

At noon, _____ ate lunch at the host’s home. The host served many dishes. Alaina thought the host was much too friendly but she didn’t know _____ to do with the dishes. In France, each time people only have one plate of dish. So Alaina _____ get used to this method of treating guests.

After that day, Alaina has learned more about Chinese culture and has gradually become a China hand. Now she knows if she puts down the cup, the host ______ offering her tea. And if she says she has been full, the host will not serve her dishes.

I went to the restaurant on the ground floor of the hospital with my mother. We took our ________ and then walked back to the 5th floor where my father stayed. In, the evening when we were leaving, I found the wallet in my bag was ________.

I had put lots of money in it since I had to pay some bills. I started to ________ worriedly. And then I remembered my visit to the restaurant a few hours ago. On my way there, I was quite disappointed at my ________. And I hoped that nobody would have taken away the wallet.

The restaurant was ________ when I entered it. There were no customers. Just a couple of waitresses were hanging around. I asked them if they had seen a gray wallet. They told me to check with the ________ named Rani who was cleaning the floor. When I ________ Rani, she told me to check on the counter.

________, the wallet was there. All the money was in the wallet, too. Rani told me how she ________ the wallet while cleaning the table. She said she just put it on the counter as usual. Rani was ________. I was so glad to meet a person like her.

9 . Mobile phone has become a problem for middle schools. Some middle schools in Australia have banned (禁止) students from carrying mobile phones during school hours.

Mobile phone use among children has become a problem for the school this year. Several children have got mobile phones as Christmas gifts, and more students will want them.

Marry Bluett, an official, said mobile phone use is a distraction (分心的事) to students during school hours and it also gives teachers so much trouble in their classrooms. Teachers were also saying that sometimes students might use phone messages to deceive during exams.

She said some schools had tried to ban mobile phones. Some parents felt unhappy because they couldn’t get in touch with their children.

Many teachers said students should not have mobile phones at school, but if there was a good reason, they could leave their phones at school office. They also said there were many reasons why the students should not have mobile phones at school: they were easy to lose and were a distraction from studies.

Many people say that they understand why parents would want their children to have phones, but they think schools should let the students know when they can use their mobile phones.