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 behavior. 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 dies away. Other nearby ants then notice 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.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. |
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 |
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. |
Here in the hills were buffaloes (野牛). I had even, in my very young days — when I could not live till I had killed one of each kind of African animal — shot a bull out there. Later on, when I was not so interested to shoot as to watch the wild animals, I had been out to see them again. But twice I had to go back without success.
But one afternoon as I was having tea with some friends outside the house, Denys came flying from Nairobi and went over our heads westwards; a little while after he turned and came back and landed on the farm. I drove down to the plane to bring him back, but he would not get out of his plane.
“The buffaloes are out feeding in the hills,” he said, “come out and have a look at them.”
“I cannot come,” I said. “I have got a tea-party up at the house.”
“But we will go and see them and be back in a quarter of an hour,” he said.
This sounded to me like the suggestions which people make to you in a dream. So I went up with him. It did not take us long to see the buffaloes from the air; we counted them as they peacefully mixed and separated on the open ground closed in by bushes. There was one very old big black bull, and a number of young ones; if a stranger had come near to them they would have heard or smelt him at once, but they were not prepared for something from the air. They heard the noise of our machine and stopped feeding, but they did not seem to be able to look up. In the end they realized that something very strange was about; the old bull first walked out in front of the others. Suddenly he began to go down the valley side and after a moment he broke into a run. The whole group now followed him, rushing hurriedly down into the buses. In a small wood of low trees they stopped and kept close together. Here they believed themselves to be out of sight. We flew up and away. It was like having been taken there by a secret unknown route.
When I came back to my tea-party the teapot on the stone was still so hot that I burned my fingers on it.The writer drove to the plane ________.
| A．to pick Denys up and take him back to the tea-party |
| B．to have a talk with Denys |
| C．to do some repairs for Denys |
| D．because they wanted to go up in the plane |
Denys said it would only take a quarter of an hour to go and see the buffaloes ________.
| A．but it took much longer than that | B．and he was right |
| C．if they went by a secret route | D．but it wasn’t a serious suggestion |
When the buffaloes heard the noise of the plane, they ________.
| A．looked up at it | B．ran away immediately |
| C．continued feeding | D．were uncertain what to do |
Dear Betty,
My roommate’s family wants me to celebrate Thanksgiving Day with them in their home. I accepted the invitation, and I’m excited about going, but I’m a little nervous about it, too. The social customs in my country are different from those here, so I’m a little worried about making mistakes.
Should I bring a gift, such as candy or flowers? Should I arrive on time or a little late? At the dinner table, how can I know which fork or knife to use? How can I let the family know that I’m thankful for their kindness?
Yours,
Knowing Nothing
Dear Knowing Nothing,
It’s a good idea to bring a gift when you go to a dinner party. Flowers are always welcome, or you can bring a bottle of wine if you know the family drink it.
You should arrive on time or five to ten minutes late. Don’t get there early. If you are going to be more than fifteen minutes late, you should call and tell them.
Try to relax at the dinner table. If you don’t know how to use the right fork, knife or spoon, just watch the other guests, and follow them. If you still have no idea of what to do, don’t be shy about asking the person next to you; it’s better to ask them than to be silently uncomfortable and nervous.
If you like the food, say so. Of course, you’ll thank the host and hostess for the meal and for their kindness. It’s also a good idea to send a card to thank them the day after.
Yours,
Betty Knowing Nothing wrote a letter to Betty to _____.
| A．tell Betty some good news | B．ask for some advice |
| C．answer some questions | D．invite her to dinner |
According to Betty, Knowing Nothing ______ when going to a dinner party.
| A．can only bring some flowers |
| B．can’t bring wine |
| C．should arrive on time or five to ten minutes late |
| D．should arrive twenty minutes late |
Betty does NOT advise Knowing Nothing to _____.
| A．relax at the dinner table | B．watch the other guests |
| C．ask the person beside him | D．keep silent at table |
One night last February, a seventeen-year-old Duffy drove home along a winding road, he saw a strange light thrown against the tree. “I knew it wasn’t the moon”, he said. “I drive this road all the time and I notice little things out of place.”
Duffy stopped his car and got out to examine. Below him far down in the deep valley lay a broken car with its headlights on. Thirty minutes earlier, a man had driven off the edge of the road, which has no guardrail. His car fell and rolled end over end, landing on its top more than two hundred feet below.
Duffy rushed to call for help, then returned and got down to reach the injured driver. Snow covered the valley and the temperature was below freezing. After struggling back up the cliff, Duffy took off his jacket and shirt and wrapped the injured man in time, along with the blankets from his car.
Life-saving deeds are starting to become usual action for Duffy, the oldest of seven children. When he was 12, he saved his ten-year-old brother from drowning. Two years ago, his three-year-old sister ate rat poison, and Duffy cleaned out her mouth, make her drink milk to protect her stomach and called doctors.
“We have tried to teach the children good values, and it looks like we have got some reward for it.” His father says. The strange light came from ________.
| A．The bright moon. | B．Duffy’s car. |
| C．The broken car in the valley | D．an unknown place |
The phrase” landing on its top” means the car lay_________.
| A．on the top of the cliff | B．with its wheels upward |
| C．with its head upward | D．on the road as usual |
From the above article, we can see Duffy has saved ________ at least.
| A．two | B．three | C．four | D．five |
“We have tried to teach the children good values” may probably mean Duffy’s parents often tell their children_________.
| A．to help people in danger | B．how to save people’s lives |
| C．to remember the value of the car | D．how to do business |
This is a true story from Guyana. One day, a boy took a piece of paper from a box. He made a paper ball and pushed it into his nose. He couldn’t get it out. He ran crying to his mother. His mother couldn’t get the paper out, either. A week later, the paper was still in the boy’s nose. His nose began to have a bad smell.
So his mother took the boy to a hospital. The doctor looked up at the child’s nose, but she couldn’t get the paper out. She said she had to cut the boy’s nose to get the paper out.
The boy’s mother came home looking sad. She didn’t want her child to have his nose cut. The next day she took the boy to her friend Sidney who lived in a house with an old lady called May. May wanted to see the child, so the child let her look up his nose.
“Yes, I can see it,” May said. “It will be out soon.”
As she spoke, she shook some black pepper on the child’s nose. The child gave a mighty sneeze and the paper flew out. His mother was surprised. May told his mother to take the boy to the seaside for a swim, for the salt water would go up his nose and stop the bad smell.
So the lucky boy didn’t have to go to the hospital to have his nose cut. After the boy pushed a paper ball into his nose, ____.
| A．he took it out | B．his mother took it out |
| C．he did nothing but cry | D．he tried to take it out but failed |
The paper ball stayed in the boy’s nose for ____.
| A．at most seven days | B．less than seven days |
| C．more than seven days | D．exactly seven days、 |
Which of the following is TRUE?
| A．The doctor helped to take the paper ball out of the boy’s nose. |
| B．May succeeded in taking the paper out. |
| C．The boy’s mother found some black pepper to solve the problem. |
| D．The boy had to have his nose cut at last. |
The boy should be taken to the seaside for a swim because ____.
| A．he needed to learn to swim |
| B．the sea water would stop the bad smell of his nose. |
| C．the sea water would wash out the paper ball. |
| D．he needed a rest |
The clock struck eleven at night. The whole house was quiet. Everyone was in bed except me. Under the strong light, I looked sadly before me at a huge pile of that troublesome stuff they call “books”.
I was going to have my examination the next day. “When can I go to bed?” I asked myself. I didn’t answer. In fact I dared not.
The clock struck twelve. “Oh, dear!” I cried. “Ten more books to read before I can go to bed!” We pupils are the most wretched creatures in the world. Dad does not agree with me on this. He did not have to work so hard when he was a boy.
The clock struck one. I was quite desperate now. I forgot all I had learned. I was too tired to go on. I did the only thing I could. I prayed, “Oh God, please help me pass the exam tomorrow. I do promise to work hard afterwards, Amen.” My eyes were so heavy that I could hardly open them. A few minutes later, with my head on the desk, I fell asleep. The underlined word “wretched” in Paragraph 3 probably means ____________.
| A．happy | B．disappointed | C．unhappy | D．hopeful |
Reviewing his lessons that night didn’t help him because ____________.
| A．it was too late at night |
| B．he was very tired |
| C．his eyelids were so heavy that he couldn’t keep them open |
| D．he hadn’t studied hard before the examination |
What do you suppose probably happened to the author the next day?
| A．He went to a church to pray again. | B．He passed the exam all by luck. |
| C．He failed in the exam. | D．He was punished by his teacher. |
The best title for the passage would be ____________.
| A．The Night Before the Examination | B．Working Far into the Night |
| C．A Slow Student | D．Going Over My Lessons |