用作副词(adv.)

When did that happen?那件事是什么时候发生的？

They stood respectfully when he entered the room.当他走进房间时，他们都恭恭敬敬地站着。

Iron will melt when it is made very hot.当铁烧得很热时就会熔化的。

用作连词(conj.)

And they roared when Seaman held up two fingers.然后当希曼伸出两根指头的时候他们就吼叫起来。

I stayed till noon, when I went home.我留到中午，然后就回家了。

When all is said and done,we still must eat.可是说到底，我们还得吃饭。

But when I returned the door was open.可是回来时门是开着的。

How can they learn anything when they spend all their spare time watching television?他们把所有的空闲时间都用来看电视了，还能学什麽东西呢？

It was the sort of morning when everything goes wrong.那天上午就是那样，事事不顺心。

He entered on his inheritance when he was 21.他21岁时继承了财产。

用作副词(adv.)

When did you see him last?
你上次是什么时候见到他的?

I'd pke to know when they will let him out.
我想知道他们什么时候能让他出去。

I don't know when to start.
我不知道何时开始。

This is the hour when the place is full of people.
这种时候这地方到处都是人。

We will put off the meeting till next week,when we will be all here.
会议将推迟到下周,那时我们都在这儿。

That was when I was eight.
那是我八岁时的事情了。

用作连词(conj.)

Often she will weep when alone.
她一个人时常哭。

When he comes I'll tell him to fetch the popce.
他来的时候我将让他去喊警察来。

I was walking along the street when someone called me from behind.
我正沿着街道走时,忽然后面有人喊我。

When the weather is good,I usually go to the country.
若是天气好的话,我总是到乡下去。

Hardly had I opened the door when I hit him.
我刚刚打开门就撞到他。

He sold it for 10 dollars when everyone else sold it for 12.
别人卖12元,他却卖10元

adv.(副词)

when的基本意思是“什么时候”。可用作疑问副词,用来询问某事曾发生或将要发生的时间,引导特殊疑问句; 还可用作关系副词引导限制性定语从句、非限制性定语从句和表语从句,表示“是…时候的事”。

conj.(连词)

when可用作从属连词,引导状语从句,表示时间时作“当…时,在…的时候”解; 表示条件时作“如果,要是”解; 表示对比时作“既然,考虑到”解。当when所引导的从句的主语和主句的主语一致时,常将其主语、系动词或助动词省去,只留实义动词或表语,或者改写为短语。

when所引导的时间状语从句用一般现在时代替将来时,用现在完成时代替将来完成时。

用作副词(adv.)

When did that happen?那件事是什么时候发生的？

They stood respectfully when he entered the room.当他走进房间时，他们都恭恭敬敬地站着。

Iron will melt when it is made very hot.当铁烧得很热时就会熔化的。

用作连词(conj.)

And they roared when Seaman held up two fingers.然后当希曼伸出两根指头的时候他们就吼叫起来。

I stayed till noon, when I went home.我留到中午，然后就回家了。

When all is said and done,we still must eat.可是说到底，我们还得吃饭。

But when I returned the door was open.可是回来时门是开着的。

How can they learn anything when they spend all their spare time watching television?他们把所有的空闲时间都用来看电视了，还能学什麽东西呢？

It was the sort of morning when everything goes wrong.那天上午就是那样，事事不顺心。

He entered on his inheritance when he was 21.他21岁时继承了财产。

用作副词(adv.)

When did you see him last?
你上次是什么时候见到他的?

I'd pke to know when they will let him out.
我想知道他们什么时候能让他出去。

I don't know when to start.
我不知道何时开始。

This is the hour when the place is full of people.
这种时候这地方到处都是人。

We will put off the meeting till next week,when we will be all here.
会议将推迟到下周,那时我们都在这儿。

That was when I was eight.
那是我八岁时的事情了。

用作连词(conj.)

Often she will weep when alone.
她一个人时常哭。

When he comes I'll tell him to fetch the popce.
他来的时候我将让他去喊警察来。

I was walking along the street when someone called me from behind.
我正沿着街道走时,忽然后面有人喊我。

When the weather is good,I usually go to the country.
若是天气好的话,我总是到乡下去。

Hardly had I opened the door when I hit him.
我刚刚打开门就撞到他。

He sold it for 10 dollars when everyone else sold it for 12.
别人卖12元,他却卖10元

【近义词】

• while当 ... 的时候...
• once一次
• after以后
• as soon as一 ... 就
• say说
• as同样地
• why为什么
• where在哪里