when在定语从句中用法

当先行词（就是要被修饰的词）是表示时间的day,year,the time 等时候，用关系副词when 来链接定语从句，在句子里面是做时间状语，表示在...时候 。

　　定语从句--关系副词when

关系副词when在定语从句中用作状语，表示时间，用以修饰表示时间的先行词；在许多情况下可以理解为“介词+which”的意思(which的意思与先行词所表示的意思等价)，其中的“介词”通常应根据先行词的含与搭配来确定。如：

1988 was the year when he was born. 1988是他的出生年。

句中的when he was born为修饰the year的定语从句，关系副词when在此相当于in which。表示在某一年，英语习惯上用介词in，如in 1988, in 2008等，所以此处用in which。

I’ll never forget the day when I first met you.我永远不会忘记第一次见你的那天。

句中的when I first met you为修饰the day的定语从句，关系副词when在此相当于on which。表示在某一天，英语习惯上用介词on，如on that day, on Friday等，所以此处用on which。

Don’t forget the time when the wedding will start.不要忘记婚礼开始的.时间。

句中的when the wedding will start为修饰the time的定语从句，关系副词when在此相当于at which。表示在某一时刻，英语习惯上用介词at，如at that time, at the moment等，所以此处用at which。

　　定语从句引导词 when

例

The nightwhen we took a stroll in the parkwas so cold.

咱们在公园散步的那个晚上好冷。

night 做主语，被定语从句when we took a stroll in the park 修饰。

I remember the nightwhen we took a stroll in the park.

我记得那个咱们一起在公园散步的夜晚。

night变成了宾语，被定语从句when we took a stroll in the park修饰。

What I can never forget is the nightwhen we took a stroll in the park.

我永不能忘记的是咱们一起在公园散步的那个夜晚。

night变成了表语，被定语从句when we took a stroll in the park修饰。

以上三组例句中，when后面所接的都是完整句，并且when 后的从句时态和主句一致。前提是when充当的从句的时间状语，相当于是at the night.

所以，以上三句，可以把when都改成at which。

写作必备when引导定语从句句式：

There was a time when...... 曾经。。。

There was a time when people were never bothered by pollution.

曾经人们不用为污染烦忧。

We all experience a day when......我们都经历过。。。

We all experience a day when everything goes wrong.

我们都经历过事事不顺心的一天。

we can never ignore the time when......我们绝不能忽视。。。

We can never ignore the time when computers penetrate our life and study.

我们不能忽视这个电脑渗透进我们的生活和学习的年代。

　　做题，试一试：(when or which ?)

I still remember that Sunday _____ he invited me to his hometown.

I still remember that Sunday _____ was his cat's birthday.

The time _____ he gave us was not enough.

The holiday _____ we spent in Shanghai was wonderful !

The holiday ______ we traveled to Shanghai was wonderful!

1. he invited me to his hometown on that Sunday 有介词！做状语！用when，不能省！

2. That Sunday was his cat's birthday.做主语，是个名词！用which，不能省！

3. He gave us the time. 做宾语，是个名词！用which，且可以省

4. We spent the holiday in Shanghai.做宾语，是个名词！用which，且可以省

traveled to Shanghai during the holiday. 有介词！做状语！用when，不能省！

还有一点：倘若介词尚在，就不要用when,因为when = during/in/on/at 等介词＋which 里面有介词，用了就重复了！！！