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 is stronger than 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.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.

3.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.

4.What is mainly discussed in the passage?

A. experiments about how ants manage to keep their nests clean.  

B. experiments about why ants have special chemicals on their bodies.

C. experiments about why ants can have this removal behavior

D. experiments about how to decide whether an ant is dead or not.

 

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。选项中有两项为多余选项。

The Internet has opened up a whole new online world for us to meet, chat and go where we’ve never been before.

But just as in face-to-face communication, there are some rules of behavior that should be followed when on line.  1. . Imagine how you’d feel if you were in the other person’s shoes.

For anything you’re about to send: ask yourself, “Would I say this to the person’s face?” If the answer is no, rewrite and reread.    2.    

If someone in the chat room is rude to you, your instinct (本能) is to fire back in the same manner. But try not to do so.   3.  If it was caused by a disagreement with another member, try to fix the situation by politely discussing it. Remember to respect the beliefs and opinions of others in the chat room.

   4.   Offer advice when asked by newcomers, as they may not be sure what to do or how to communicate. When someone makes a mistake, whether it’s a stupid question or an unnecessarily long answer, be kind about it. If it’s a small mistake, you may not need to say anything. Even if you feel strongly about it, think twice before saying anything. Having good manners yourself doesn’t give you license to correct everyone else.  5.  At the same time, if you find you are wrong, be sure to correct yourself and apologize to those that you have offended(冒犯).

It is not polite to ask others personal questions such as their age, sex and marital status. Unless you know the person very well, and you are both comfortable with sharing personal information, don’t ask such questions.

A. If you do decide to tell someone about a mistake, point it out politely.

B. It’s natural that there are some people who speak rudely or make mistakes online.

C. Repeat the process till you feel sure that you’d feel comfortable saying the words to the person’s face.

D. Everyone was new to the network once.

E. The basic rule is simple: treat others in the same way you would want to be treated.

F. When you send short messages to a person online, you must say something beautiful to hear.

G. You should either ignore the person, or use your chat software to block their messages.

 

 0  55701  55709  55715  55719  55725  55727  55731  55737  55739  55745  55751  55755  55757  55761  55767  55769  55775  55779  55781  55785  55787  55791  55793  55795  55796  55797  55799  55800  55801  55803  55805  55809  55811  55815  55817  55821  55827  55829  55835  55839  55841  55845  55851  55857  55859  55865  55869  55871  55877  55881  55887  55895  151629 

违法和不良信息举报电话:027-86699610 举报邮箱:58377363@163.com

精英家教网