定语从句例句when的用法

定语从句when的用法：

　　关系副词when主要用于修饰表时间的名词，同时它在定语从句中用作时间状语。如：

There comes a time when you have to make a choice. 你必须作出抉择的时候到了。

Gone are the days when they could do what they liked. 他们为所欲为的日子一去不复返了。

We’ll put off the picnic until next week, when the weather may be better. 我们将把野餐推迟到下星期，那时天气可能会好一点。

注意不要一见到先行词为时间名词，就以为一定要用关系副词when来引导定语从句，同时还要看它在定语从句中充当什么成分——如果在定语从句中用作时间状语，就用when;如果在定语从句中不是用作时间状语，而是用作主语或宾语，那就不能用when，而要用that, which等。如：

Don’t forget the time (that, which) I’ve told you. 不要忘记我告诉你的时间。

关系代词that / which在定语从句中用作动词told的宾语，正因为是用作宾语，所以也可以省略。

　　【拓展延伸】

　　定语从句用法归纳

定语从句由关系代词who、whom、whose、which、what、as和关系副词where、when、why等引导，但须记住：

　　不能引导定语从句.

2.关系词的分析须考虑它在定语从句中的成分。

一.指人的.关系代词有who、whose、whom、that. 试分析：

The old man who/whom /that we visited yesterday is a famous artist.

Miss Wang is taking care of the child whose parents have gone to Beijing .

The man with whom my father shook hands just now is our headmaster. (=The man who/whom that my father shook hands with just now is our headmaster.)注：

A. 指人时有时只用who不宜用that。

1.先行词为one、ones或anyone

(1)The comrade I want to learn from is the one who studies hard and works hard.

(2)Anyone who breaks the law should be punished.

2.先行词为these时

These who are going to Beijing are the best students of our school.

3.在there be 开头的句子中

There is a student who wants to see you.

4.一个句子中带有两个定语从句，其中一个定语从句的关系代词是that，另一个宜用who，以免重复。

The student that won the first prize is the monitor who works hards.

5.在非限制性定语从句中

A。I met a friend of mine in the street, who had just come from Japan.

B.主句以who开头的句子中,只用that,不用who。