When an ant dies, other ants take it out of the nest, often within an hour after its death. This behavior interests scientists and they wonder how ants know for sure — and so soon — that another ant is dead.
One scientist recently came up with a way to explain this ant behaviour. Dong-Hwan Choe is a biologist, a scientist who studies animals and plants. He found that ants have a chemical on the outside of their bodies that signals to other ants, “I'm dead—take me away” when it is dead.
But there's a question to answer: As we know, if an ant is dead, it stops moving. But when an ant is sleeping or knocked unconscious, it is also not moving. However, other ants don't move the living ant out of the nest. How do they know this ant is not dead? Choe found that ants have another chemical on their bodies, which tells nearby ants something like, “Wait—I'm not dead yet”when it is not dead. Choe suspects that when an ant dies, the chemical that says, “Wait I'm not dead yet”quickly goes away. When other ants detect the“dead”chemical without the“not dead yet”chemical, they move away the body.
To test his theory , Choe and his team put different chemicals on ants. When the scientists used the “I'm dead” chemical, other ants quickly moved the treated ant away. When the scientists used the“Wait—I'm not dead yet”chemical, other ants left the treated ant alone. Choe believes this behavior shows that the“not dead yet”chemical overrides the“dead” chemical when picked up by other ants. And that when an ant dies, the “not dead yet” chemical fades away. Other nearby ants then detect the remaining“dead”chemical and remove the body from the nest.[
Understanding this behavior can help scientists figure out how to stop ants from invading new places and causing problems.
1. What is the function of the first paragraph?
A. Leading the following paragraphs. B. Showing the main idea of the passage.
C. Introducing the background of the passage. D. Giving a summary of the passage.
2. Which of the following has the closest meaning to the underlined word “overrides” in the fourth paragraph?
A.is weaker than B. is stronger than C. is better than D. is worse than
3. What can we learn from the passage?
A. Living ants can also be taken away when they are not moving.
B. When an ant dies, it can tell others using a certain chemical.
C. A living ant can pretend to be dead using a special chemical.
D. Ants often use chemicals to communicate with each other.
4. Which of the following descriptions about Dong-Hwan Choe is right?
A. Choe did this study in order to stop ants from invading new places.
B. Choe is a biologist who is only interested in animals, especially in ants.
C. Choe first came up with an idea to explain this ant behavior，and then did some tests to prove his theory.
D. Choe did the research on this ant behavior on his own
Life gets noisier every day. Very few people can be free from noise of some sort or another. It doesn’t matter where you live, in the middle of a modern city, or a faraway village--- the chances are that you’ll be disturbed by jet aeroplanes, transistor radios, powered engines, etc. We seem to be getting used to noise, too. Some people feel quite lonely without background music while they’re working.
Scientific tests have shown that total silence can be a very frightening experience for a human being. However, some people enjoy listening to pop music which is very loud and this can do harm to their eardrums(耳鼓). The noise level in some discos is far above the usual safety level for heavy industrial areas.
One recent report about noise and concentration(专心) suggested that although a lot of people say that any noise disturbs their concentration, what really influences their ability to concentrate is a change in the level of noise. It goes on to say that a background noise which doesn’t change too much (music, for example) may even help people to concentrate.According to this passage, the noise pollution______.
| A．has become the worst in the countryside | B．has become better in big cities |
| C．has spread from cities to villages | D．has been controlled in modern cities |
What does background music refer to?
| A．Music played while people are working. |
| B．Music played in the backyard. |
| C．Noise that continues while you’re listening to other noises. |
| D．Music used to help people to concentrate. |
Some people have their hearing harmed______.
| A．while listening to pop music | B．in complete silence |
| C．when speaking loudly | D．while watching TV |
Which of the following isn’t included among the things causing noise?
| A．Rivers | B．Transistor radios |
| C．Powered engines | D．Jet planes |
Scientist have discovered that what prevents people from concentrating on something is_____.
| A．all kinds of noise | B．great changes in the level of noise |
| C．background noise | D．popular music |
For many years Henry had been a journalist. He had worked on many international newspapers and magazines and traveled over the world.
Henry had witnessed war and natural disasters such as floods, earthquakes and erupting volcanoes ( 火山爆发).
He had reported on serious accidents such as major fires and airline crashes.
He had seen every kind of terrible crime and strange event there was.
He had met and written about some of the most unusual people in the world.
In fact, there wasn’t much that Henry had not seen or done.
Now he was retired from journalism(新闻业). He owned a very expensive restaurant and spent his days talking to his wealthy and important customers. He liked to say that nothing surprised him.
One day he was sitting at the bar in his restaurant when a big gorilla(大猩猩) walked in and asked for a table.
Henry showed no surprise. He took the gorilla to a table and handed him a menu. He treated him politely and pretended there was nothing at all strange about having a gorilla in his restaurant.
The gorilla looked through the menu and ordered a salad.
Henry served the gorilla his salad personally, knowing that his waiters and waitresses would be too frightened.
At last the gorilla finished his salad and asked for the bill.
Henry wrote out the bill and handed it to the big animal.
The gorilla studied it, shook his head sadly then gave Henry fifty dollars.
“Thank you,” Henry said, and then to make conversation, he added, “we don’t get many gorillas in this restaurant.”
“At fifty dollars for a salad,” the gorilla said, “I’m not surprised.” According to the story, Henry had________.
| A．had the most exciting experiences | B．told the longest stories |
| C．made history | D．caused accidents |
One day when a gorilla came into the restaurant, Henry was_____.
| A．very surprised by the gorilla | B．not disturbed(烦忧) by the gorilla |
| C．very interested in the gorilla | D．scared of the gorilla |
From the sentences “Henry served the gorilla his salad personally, knowing that his waiters and waitresses would be too frightened” you can learn that______.
| A．his staff were not brave people | B．Henry didn’t normally serve customers |
| C．the gorilla had eaten there before | D．the gorilla was careful with his money |
I was in lodgings (寄宿处) now, on my own, but the other lodgers had constant visitors up and down the stairs past my door. None of this disturbed me except one girl who sang softly to herself an old Russian folk song as she ran up to the room above. It was a sound of sweetness, musical, soft, unselfconscious and happy. I began to listen out for it, jumped up from my table, and threw open the door to catch a glimpse(一瞥) of her as she passed, but I was always too late. I asked the people upstairs who she was, and described the beautiful sounds she made. They became rather reserved(拘谨) and exchanged glances and hurriedly admitted it might be Sally. I thought she was someone special, not to be discussed in the ordinary way, and became a little curious to meet her. But the last thing I wanted at that stage was to get caught up with anybody. I’d just come to the end of a rather painful friendship, and now I had work to do.
One day, I came face to face with a girl on the landing. It was certainly her; whoever made that noise would look as she did. We stood and stared at each other too long for comfort. I broke the moment and, excusing myself, moved past her because it was too like the movies. I thought for some time of that long, silent stare, and laughed. She was tall and looked proud, with a slight , round-shouldered look that made me breathless and I didn’t know why.At his lodgings, the author __________.
| A．seldom had visitors |
| B．wished he had more visitors |
| C．was always disturbed by other people’s visitors |
| D．had too many visitors. |
Whenever the author heard the sound of the girl’s voice__________.
| A．he sat listening to it | B．he saw her moving upstairs |
| C．he threw down his books | D．he tried to see who it was |
People who were asked about the girl__________.
| A．told him all about her | B．didn’t want to tell him much |
| C．didn’t tell him anything | D．were angry when he mentioned her |
From this passage we can see that the author was____________.
| A．was not interested in Sally | B．curiously attracted by Sally |
| C．angry at being disturbed by Sally | D．afraid to get to know Sally |
NOT all memories are sweet. Some people spend all their lives trying to forget bad experiences. Violence and traffic accidents can leave people with terrible physical and emotional scars. Often they relive these experiences in nightmares.
Now American researchers think they are close to developing a pill, which will help people forget bad memories. The pill is designed to be taken immediately after a frightening experience. They hope it might reduce, or possibly wipe out, the effect of painful memories.
In November, experts tested a drug on people in the US and France. The drug stops the body releasing chemicals that fix memories in the brain. So far the research has suggested that only the emotional effects of memories may be reduced, not that the memories are wiped out. They are not sure to what degree people’s memories are affected.
The research has caused a great deal of argument. Some think it is a bad idea, while others support it.
Supporters say it could lead to pills that prevent or treat soldiers' troubling memories after war.
They say that there are many people who suffer from terrible memories.
"Some memories can ruin people's lives. They come back to you when you don't want to have them in a daydream or nightmare. They usually come with very painful emotions," said Roger Pitman, a professor of psychiatry at Harvard Medical School. "This could relieve a lot of that suffering."
But those who are against the research say that maybe the pills can change people’s memories and changing memories is very dangerous because memories give us our identity. They also help us all avoid the mistakes of the past.
"All of us can think of bad events in our lives that were terrible at the time but make us who we are. I'm not sure we want to wipe those memories out, "said Rebecca Dresser, a medical ethicist.The passage is mainly about.
| A．a new medical invention |
| B．a new research on the pill |
| C．a way of wiping out painful memories |
| D．an argument about the research on the pill |
The drug tested on people can.
| A．cause the brain to fix memories |
| B．stop people remembering bad experiences |
| C．prevent body producing certain chemicals |
| D．wipe out the emotional effects of memories |
We can infer from the passage that.
| A．people doubt the effects of the pills |
| B．the pill will certainly stop people's emotional memories |
| C．taking the pill will do harm to people's physical health |
| D．the pill has already been produced and used by the public in America |
Which of the following does Rebecca Dresser agree with in the last paragraph ?
| A．some memories can ruin people's lives. |
| B．people want to get rid of bad memories. |
| C．experiencing bad events makes us different from others. |
| D．the pill will reduce people's sufferings from bad memories. |
You may probably read the passage in __________
| A．a guidebook | B．a textbook |
| C．a medical magazine | D．a science fiction |
The national assistance system for poor college students is getting more effective as proved by fewer phone calls to the hotline of the National Center for Student Assistance Administration.
"Poor college students and their parents are getting more satisfied with the national assistance system," said Ma Wenhua, deputy director of the administration, on Saturday. Over the past three years, the hotline received 8,488 calls. Statistics show 62 percent of the calls were made to ask about the funding policy, while 38 percent (3,200 calls) complained local colleges had failed to abide by the rules to support the students.
Complaints were seen a year-on-year decrease from 2006 to 2008. Ma said some poor families might still overlook what they should do to get support for their child. To ensure education equality, the government has introduced a set of favorable policies to help poor students, such as scholarships, grants(助学金), student loans, tuition waivers(学费全免) and the work-study programs under which poor students are helped out in libraries, teachers' offices or service departments to earn money.
Statistics show the government spent 29.3 billion yuan last year to aid college students, up 7.6 percent from the previous year. Around 40 million persons of college students received the national aid.
The Ministry of Education of the government would ensure that no students drop out of colleges or universities because of poverty.
Among the 20 million students in the country's public and private universities and colleges last year, about 20 percent came from poor backgrounds, official figures show.The national assistance system is set up ___.
| A．for parents and students to complain |
| B．to help poor college students |
| C．for poor students to get free education |
| D．to help students find jobs |
The underlined phrase "abide by" in the second paragraph probably means ____.
| A．follow | B．break | C．bear | D．agree to |
From the passage, we know that ____.
| A．students will drop out of university because of poverty |
| B．Chinese poor college students are more satisfied with national assistance system |
| C．more and more parents are complaining about their local colleges |
| D．college students are suffering from great economic pressure |