when用法

when的从句主句各可以用哪一种动词。(全部)
例:while 主句延续性动词,从句延续性动词。

1、adv.

(1)什么时候,何时,什么情况下,什么场合下

I'd like to know when they'll let him out.我想知道他们什么时候放他。

(2)(用语时间的表达方式之后)在那时,其时 

The Queen's last visit was in May, when she opened the new hospital.女王上次来访是在五月份,她那时主持了这座医院的落成典礼。

(3)其时,当时,当场 

2、conj.

(1)在……时候,当……时,在……期间 

Here the local were always barbered at this hour on this day.原来本地人老是在这一天这个时候这个地方理发。

(2)在……之后 

When I mingled with other families I distinctly discerned how peculiarly fortunate my lot was.在我接触到别的一些家庭之后,我清楚地体会到自己可谓得天独厚的天之骄子。

(3)在任何……时候 

You can save the game at any time when you're at your bunk.任何时候你都可以在你的床位储存你的游戏。

(4)一……就,刚……就 

He is prone to lose his temper when people disagree with him.人家一不同意他的意见,他就发脾气。

(5)考虑到,既然 

Why use wood when you can use plastic?既然能用塑料,何必非用木料?

3、n.时间 time

4、pron.

什么时候,何时 

Considerate products know when to bend the rules 体贴的软件知道什么时候调整规则。

扩展资料

when, while, as 表示“在……的时候”的意思。这些连词均可表示“当……时”引出时间从句。

when所引导的从句,其谓语动词既可是持续动词,也可是短暂动词;谓语动词动作发生的时间可以与主句谓语动词的动作是同时,或之前、之后。

while句中的谓语动词应为持续动词,不用短暂动词,谓语动作发生的时间通常与主句谓语动词动作发生时间是同时。

as侧重指从句与主句的动作同时进行,谓语动词可以是持续性的,可以是短暂性动词。

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第1个回答  2020-04-11
1、由when引导的时间状语从句,主句用过去进行时,从句应用一般过去时;如果从句和主句的动作同时发生,两句都用过去进行时的时候,多用while引导,如: a. when the teacher came in, we were talking. 当此句改变主从句的位置时,则为: while we were talking, the teacher came in. b. they were singing while we were dancing. 2、when和while 还可作并列连词.when表示“在那时”;while表示“而,却”,表对照关系.如: a. the children were running to move the bag of rice when they heard the sound of a motor bike. 孩子们正要跑过去搬开那袋米,这时他们听到了摩托车的声音. b. he is strong while his brother is weak. 他长得很结实,而他弟弟却很瘦弱. 3、when,while引导时间状语从句的区别 一、when可以和延续性动词连用,也可以和短暂性动词连用;而while只能和延续性动词连用. ① why do you want a new job when youve got such a good one already?(get为短暂性动词)你已经找到如此好的工作,为何还想再找新的? ②sorry,i was out when you called me.(call为短暂性动词)对不起,你打电话时我刚好外出了. ③strike while the iron is hot.(is为延续性动词,表示一种持续的状态)趁热打铁. 二、when从句的谓语动词可以在主句谓语动作之前、之后或同时发生;while从句的谓语动作必须是和主句谓语动作同时发生. 1.从句动作在主句动作前发生,只用 when. ①when he had finished his homework,he took a short rest.(finished先发生)当他完成作业后,他休息了一会儿. ②when i got to the airport,the guests had left.(got to后发生)当我赶到飞机场时,客人们已经离开了. 2.从句动作和主句动作同时发生,且从句动作为延续性动词时,when,while都可使用. ①when /while we were dancing,a stranger came in.(dance为延续性动词)当我们跳舞时,一位陌生人走了进来. ②when /while she was making a phonecall,i was writing a letter.(make为延续性动词)当她在打电话时,我正在写信. 4.在将来时从句中,常用when,且从句须用一般时代替将来时. ①you shall borrow the book when i have finished reading it.在我读完这本书后,你可以借阅. ②when the manager comes here for a visit next week,ill talk with him about this.下周,经理来这参观时,我会和他谈谈此事. 三、when用于表示“一……就……”的句型中(指过去的事情). sb.had hardly(=scarcely) done sth.when...=hardly / scarcely had sb.done sth.when... ①i had hardly /scarcely closed my eyes when someone knocked at the door.=hardly / scarcely had i closed my eyes when someone knocked at the door.我刚一闭上眼,就有人在敲门了. ②i had hardly /scarcely entered my room when the telephone rang.=hardly /scarcely had i entered my room when the telephone rang.我刚一走进房门,电话就响了.
第2个回答  2020-04-23

when

adv.    什么时候; 何时; 什么情况下; 什么场合下; (用于时间的表达方式之后) 在那时; 其时; 当时; 当场;    

pron.    什么时候; 何时;    

conj.    在…时候; 当…时; 在…期间; 在…之后; 在任何…时候;    

[例句]When are you going home?

你什么时候回家?

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第3个回答  推荐于2017-11-27
一、作为副词,它有以下的用法:
1. 作为疑问副词,引导特殊疑问句,意为“什么时候;何时”。

如: ( 1 ) When will they come back?

( 2 ) What time will they come back?

回答 when 引导的从句,不一定指出具体的时间点。如回答句( 1 )可用 tomorrow, next month 等。而回答 what time 引导的问句,则必须说出具全的时间点,如 at two o'clock, at five past ten 等。

2. 作连接副词,引导名词性从句或不定式,意为“什么时候”。从句使用陈述句语序,时态根据实际情况而定。

如: ( 1 ) I'd like to know when they will come. 我想知道他们什么时候来。( when 引导宾语从句)

( 2 ) Can you tell me when the bank opens? 你能告诉我银行什么时候开门吗?( when 引导宾语从句)

( 3 ) When she'll be back depends much on the weather. 她何时回来在很大程度上取决于天气。( when 引导主语从句)

( 4 ) Have you decided when to go sightseeing? 你们已经决定什么时候去郊游了吗?( when 引导不定式结构)

3. 作疑问代词,常和介词 since, till, up to 等连用,意为“什么时候”。

如: ( 1 ) Since when have they had the house? 他们从什么时候起有这幢房子的?

( 2 ) Till when is the library open? 图书馆开放到几点呢?

4. 作关系副词,引导限制性定语从句和非限制性定语从句。

如: ( 1 ) The days are gone forever when the Chinese people were looked down upon. 中国人民被人轻视的日子一去不复返了。

( 2 ) The main school holidays are from mid-December till early February, when the days are long and warm. 学校的主要假期是从 12 月中旬到 2 月初,这段时间里白天长而且很温暖。

( 3 ) Considering (the time) when these paintings were done, they are in excellent condition. 考虑到这些油画的创作时期,它们保存的状况是极好的。

( 4 ) Do you remember (the time) when the three of us went on a picnic? 你还记得我们三个人去野餐的那段时光吗?

在定语从句中, that 在某些条件下可用来代替 when ,这时其先行词通常是 time, day, moment, year 等。

如: ( 1 ) His mother died on the evening that he was born. 他母亲死于他出生的那晚。

( 2 ) I stay at home on the days that I am not busy. 在我不忙的时候,我就呆在家里。

在某些含有“时间”的名词词组后面,由于该名词不表示时间,或整个名词词组已用作连词,所以不用 when 引导。如: the moment, the instant, the minute, the second 等等,意为“一……就……”,引导时间状语从句。

如: ( 1 ) The first time I went to China, I visited Beijing. 我第一次来中国就游览了北京。

( 2 ) I thought her nice and honest the first time I met her. 我第一次见到她时就认为她很诚实。

( 3 ) The instant I saw him I knew he was my brother. 我一看到他就知道他是我兄弟。

二、作为从属连词,引导状语从句,表示多种语法意义:

1. 表示时间,意为“当……时;在……的时候”。

A. 在时间、条件等状语从句里,用一般现在时表示将来时;当需要表达将来完成的意义时,必须使用现在完成时来代替。

如: ( 1 ) When you see him, please say hello to him. 见到他时,代我问他好。

( 2 ) When you have finished your experiment, please tidy the lab and put everything back in the cupboards. 当你们做完实验后,请把实验室整理好并把物品放回柜子中。

B. 表示过去发生的事情,在 when 引导的时间状语从句的主从复合句中,动作发生在先的用过去完成时,在后的用过去时。

如: ( 1 ) When I was in Japan, I bought some beautiful pearls. 我在日本时,买了一些漂亮的珍珠。

( 2 ) When I reached the station, the train had left. 当我到达火车站时,火车已经开走了。

2. 表示前面的叙述所没有提到过的信息。它总是对所描述的事件予以引人注目的强调,意为“这时;突然”;当位于句末的分句具有引种用法时,大致有以下三种情况:

A. when 分句前面的分句使用过去进行时。

如: ( 1 ) He was still smiling when the door opened and his wife came in. 他正笑着的时候,门突然开了,他妻子走了进来。

( 2 ) I was thinking of this when I heard my name called. 我正想着这件事时,突然听到有人叫我的名字。

B. when 分句前面的分句使用 was (were) about to, was (were) on the point 等。

如: ( 1 ) We were about to start when it began to rain. 我们刚要出发就开始下雨了。

( 2 ) He was on the point of leaving when someone knocked at the door. 他刚要走就有人敲门。

C. when 分句之前的分句用过去完成时,其中 sb had hardly / scarcely /barely … when 已成为固定词组。如:

( 1 ) We had hardly fallen asleep when the bell rang. 我们刚刚入睡,铃声就响了起来。

( 2 ) He had scarcely arrived when he had to leave again. 他刚刚到达就又要离开了。

3. 表示条件,相当于 if ,引导条件状语从句。

如: How can I get a job when I can't even read or write? 如果我连读和写都不会,我怎么能找到工作呢?

4. 表示对比,主要有以下两种情况:

A. 相当于 whereas, while, since, 意为“既然;然而”。

如: ( 1 ) How can I help them to understand when they won't listen to me? 既然他们不愿听我的,我又怎么能帮助他们弄明白呢?

( 2 ) They have only three copies when we need five. 他们只有三本,而我们却需要五本。

B. when 从句中使用虚拟语气,意为“本来……却……”。

如: ( 1 ) She paid when she could have entered free. 本来可以免费入场,而她却付了款。

( 2 ) She stopped trying when she might have succeeded next time. 她本来下次有可能获得成功,但她却不再尝试了。

( 3 ) They were gossiping, when they should have been working. 他们本该工作,却在那里说别人的闲话。

5. 由 when 等引导的状语从句,如果主语与主句的主语一致或是 it ,谓语动词又含 be 动词时,主语和 be 动词常常被省略,就变成“ when + V-ing/ V-ed/ adj/ 介词词组”的结构。

如: ( 1 ) When in Rome, do as Romans do. 入乡随俗。

( 2 ) When (we are ) young, we are full of hope. 年轻时,我们大家总是充满希望。

( 3 ) Don't reach sideways when standing on a ladder. 站在梯子上时,不要侧着身子去够东西本回答被提问者采纳
第4个回答  2019-11-24
1
When
I
have
money
in
the
future,
i'll
buy
a
new
bike
for
you.(
when
引导了时间状语从句,从句用一般现在时,主句用将来时)
2,When
i
came
in
,I
found
no
one
left
(
when
引导了时间状语从句,表示过去的事实,主从句都用过去时)
3.I
was
reading
a
book
in
the
room
when
a
dog
ran
in.(when=and
at
that
time)
=While
i
was
reading
a
book
in
the
room
,
a
dog
ran
in
4
Hardly
had
he
arrived
when
he
began
to
work.(
hardly.had
+主语+过去分词。。when
+主语+谓语。)

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