题目内容：

Thirty-two people watched kitty Genovese being killed right beneath their windows. She was their neighbor. Yet none of the 32 helped her. Not one even called the police. Was this in gunman cruelty? Was it lack of feeling about one's fellow man?

Not so, say scientists John Barley and Bib Fatane. These men went beyond the headlines to probe（探查） the reasons why people didn't act. They found that a person has to go through two steps before he can help. First he has to notice that is an emergency(紧急情况).

　　Suppose you see a middle-aged man fall to the side-walk. Is he having a heart attack? Is he in a coma （昏迷） from diabetes（糖尿病）? Or is he about to sleep off a drunk?

Is the smoke coming into the room from a leak in the air conditioning? Is it steam pipes? Or is it really smoke from a fire? It's not always easy to tell if you are faced with a real emergency.

　　Second, and more important, the person faced with an emergency must feel personally responsible. He must feel that he must help, or the person won't get the help he needs.

The researchers found that a lot depends on how many people are around. They had college students in to be tested. Some came alone. Some came with one or two others. And some came in large groups. The receptionist started them off on the tests. Then she went into the next room. A curtain divided the testing room and the room into which she went. Soon the students heard a scream, the noise of file cabinets falling and a cry for help. All of this had been pre-recorded on a tape-recorder.

Eight out of ten of the students taking the test alone acted to help. Of the students in pairs, only two out of ten helped. Of the students in groups, none helped.

In other words, in a group, Americans often fail to act. They feel that others will act. They, themselves, needn't. They do not feel any direct responsibility.

Are people bothered by situations where people are in trouble? Yes. Scientists found that the people were emotional, they sweated, they had trembling hands. They felt the other person's trouble. But they did not act. They were in a group. Their actions were shaped by the actions of those they were with.

1.The purpose of this passage is_________.

A．to explain why people fail to act in emergencies

B．to explain when people will act in emergencies

C．to explain what people will do in emergencies

D．to explain how people feel in emergencies

2.Which of the following is NOT true?

A．When a person tries to help others, he must be clear that there is a real emergency.

B．When a person tries to help others, he should know whether hey are worth his help.

C．A person must take the full responsibility for the safety of those in emergencies if he wants to help.

D．A person with a heart attack needs the most.

3. The researchers have conducted an experiment to prove that people will act in emergencies when__________.

A．they are in pairs	B．they are in groups
C．they are alone	D．they are with their friends

4.The main reason why people fail to act when they stay together is that _________.

A．they are afraid of emergencies

B．they are reluctant to get themselves involved

C．others will act if they themselves hesitate

D．they do not have any direct responsibility for those who need help