内容正文:
第08练 when、while、as等引导的时间状语从句
一、When/while/as(当…时候)
1)When:
when引导时间状语从句时表示“当……的时候”,when既可以指时间段也可指时间点,从句中既可用延续性动词又可用瞬间性动词,且动作既可和主句的动作同时发生又可在主句的动作之前或之后发生。且when引导的时间状语从句中一般用一般现在时表将来(主将从现)。
e.g. When I came home my wife was cooking dinner.
A)如果when引导的时间状语从句的主语与主句主语相同,而从句的谓语又是be动词时,那么从句中的主语和be可以省略;
e.g. When (you are) in trouble, ask her for help.
B)当when引导的时间状语从句的主语与主句主语相同时,往往还可以省略从句的主语并用“when+分词”的形式替代该状语从句。
e.g. When I came into the room (=When coming into the room), I found him lying there asleep.
2)While
while引导时间状语从句时表示“当……的时候”,它强调主句的动作与从句的动作同时持续地进行,用于这一用法时while引导的时间状语从句和主句中的谓语动词必须是延续性动词,或者强调主句的动作发生在从句动作的进行过程中,此时主句中的谓语动词通常是非延续性动词。记住,从句中始终是延续性动词,且从句多用进行时态。(while还可以表示对比,译成“然而”,放在句首可以表示“虽然”)
e.g. I met her while I was at school.
3)As
as引导时间状语从句时表示①“当……时”(只引导瞬间性动词,两个动作是紧密联系的,一前一后进行),②“一边……一边……”,侧重表示两个动作同时发生(包括一个主语同时进行两个动作),③“随着”,一种动作随着另一种动作的变化而变化从句中只能接延续动词。
e.g. He jumps as he goes along.
【When, while , as 辨析】
三者均可以表示“当……时候”,如果主句表示的是短暂性动作,而从句表示的是延续性动作(主短从延),三者可以通用。
I met Mr Li as / when / while I was walking along the street.
(1)While意为“在……期间”,从句的谓语必须是延续性动词。
The plane had left when we got to the airport.
(2)表示带有规律性的“每当”,或者主从句动作有先后时,都只能用when.
When winter comes, it becomes cold.
(3)表示“随着”时间的推移,主从句的内容是两种变化的情况,只能用as.
As the day went on, the weather got worse.
(4)强调主句动作延续到从句所指的整个时间,只能用while.
拓展:
before引导时间状语从句时表示主句的动作发生在从句动作之前,常翻译为在“……之前”,“……才……”或“……就……”。
after引导时间状语从句时表示主句的动作发生在从句动作之后
not ……until,主句的谓语动词则为短暂性的,表示“直到……才”
as soon as 一……就
一、单项选择
1.While she ________ TV in the sitting room, Mum ________.
A.watches; come in B.is watching; came in
C.was watching; came in D.was watching; was coming in
2.We were lying on the grass ________ a heavy rain came. We were wet all over.
A.before B.while C.as D.when
3.— Please tell Tina the news quickly. It’s very important.
— OK. I’ll tell her _____ I see her.
A.since B.before C.until D.as soon as
4. my mother was cooking this morning, my father was washing his face.
A.Although B.While C.Unless D.Because
5.—Wh