2．cause与reason

（1）cause作名词时最重要的含义是“原因”、“起因”：

A fireman accidentally discovered the cause of the fire.

一个消防队员偶然发现了起火的原因。

Do you know the cause of the war?

你知道这场战争的起因吗？（cause通常与of连用）

cause作动词时可以表示“使……产生／发生”、“引起”：

Forest fires are often caused by broken glass or cigarette ends.

森林火灾时常由碎玻璃或香烟头引起。

What caused the accident?

事故是如何造成的？

（2）reason作名词时最重要的含义是“理由”、“原因”：

Give me your reasons for going there.

请告诉我你去那里的理由。

What was the reason for the delay?

延迟的原因是什么？

作“原因”讲时，reason与cause可以互相交换使用，但reason与介词for连用，而cause则与介词of连用：

What was the cause of the delay?

（译文同上）

reason后面通常跟why引导的从句：

That was the reason why the meeting was put off.

这就是会议推迟的原因。

reason作动词时表示“推理”、“劝导”、“说服”等：

How can you reason with him when he is so worried?

他现在如此担心，你怎么能劝得了他？

3．drop与fall

drop既可作及物动词又可作不及物动词，表示“（使）掉下”、“（使）落下”、“放下”：

As he walked past the tree, an apple dropped from it.

当他走过那棵树时，一个苹果从树上掉了下来。

The waiter dropped a fork.

那侍者掉了一把叉子。

He dropped the bag on the floor.

他把包放在地板上。

fall通常为不及物动词，表示“落下”、“（雨、雪）下”、“降”、“跌倒”、“摔倒”：

I fell and hurt myself.

我摔倒了并受了伤。

Please hold the vase and don't let it fall.

请拿住这花瓶，别让它倒了。

When leaves fall in autumn, I'll come back.

秋天叶落时，我就会回来。

练习答案 Key to written exercises

1．关键句型练习答案

A What happened: began(1.2);examined(1.4);were not able to find(1.5);did not start(1.6);discovered(1.7); noticed (1.8);was wound(1.8);was able to solve(1.9);dropped (1.10); wound(1.11); it did so(1.11); sent(1.11); started(1.11)

What has happened: have put out(1.1)

What has been happening: have been trying to find(1.2)

C Jack looked at his watch for the twentieth time. Suddenly Jill arrived.

‘I've been waiting for over an hour,’he said angrily.‘You never come on time.’

‘Oh, is that so?’Jill answered.‘Were you here at  2.30?’Jack went red.‘Well,’he said,‘I go here five minutes late myself, but you weren't here.’

‘I came here at exactly  2.30,’Jill said,‘and I waited for five minutes, but you didn't come.’

‘What have you been doing since then?’Jack asked.‘I've just been to the hairdresser's,’Jill answered brightly.

2．难点练习答案

a Look: you threw the potato-peeler away by mistake.

The shepherd threw some food to his dogs.

The teacher threw some chalk at a boy who wasn't listening.

b I'm quite certain these are my glasses.

The children are very quiet. What's going on?

c The cause of unemployment is complicated.

Can you explain the reason for changing our arrangements?

He reasoned that we would have to comply, even if we didn't wish to.

d Please don't drop that vase!

It fell from my hands and broke.

3．多项选择题答案

1c  2d  3a  4c  5c  6c

7d  8c  9d  10 a  11c  12 c

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