Question

when while as 的区别

用法

Answer 1

when,
while
,as
soon
as
这三个词都有"当……时候"之意，但用法有所不同，使用时要特别注意。
①when意为"在……时刻或时期"，它可兼指"时间点"与"时间段"，所引导的从句的动词既可以是终止性动词，也可是持续性动词。如：
when
i
got
home,
he
was
having
supper.我到家时，他正在吃饭。
when
i
was
young,
i
liked
dancing.我年轻时喜欢跳舞。
②while只指"时间段"，不指"时间点"，从句的动词只限于持续性动词。如：
while
i
slept,
a
thief
broke
in.在我睡觉时,盗贼闯了进来。
辨析
①when从句与主句动作先后发生时，不能与while互换。如：
when
he
has
finished
his
work,
he
takes
a
short
rest.每当他做完工作后，总要稍稍休息一下。(when
=
after)
when
i
got
to
the
cinema,
the
film
had
already
begun.当我到电影院时，电影已经开始了。(when=before)
②when从句动词为终止性动词时，不能由while替换。如：
when
he
came
yesterday,
we
were
playing
basketball.昨天他来时，我们正在打篮球。
③当从句的谓语是表动作的延续性动词时，when,
while才有可能互相替代。如：
while
/
when
we
were
still
laughing,
the
teacher
came
in.正当我们仍在大声嬉笑时，老师进来了。
④当从句的谓语动词是终止性动词，而且主句的谓语动词也是终止性动词时,when可和as通用，而且用as比用when在时间上更为紧凑，有"正当这时"的含义。如：
he
came
just
as
(or
when)
i
reached
the
door.我刚到门那儿，他就来了。
⑤从句的谓语动词如表示状态时，通常用while。如：
we
must
strike
while
the
iron
is
hot.我们应该趁热打铁。
⑥while和when都可以用作并列连词。
mike
is
tall
while
his
brother
is
short.迈克的个子很高，然而他弟弟很矮。
mary
was
on
her
way
home
when
two
big
boys
stopped
her.玛丽正走在回家的路上，这时两个大个子男孩拦住她。
as
soon
as的用法：
（1）、as
soon
as
one
can
=
as
soon
as
possible
表示“尽可能快”之意，如：
①
you
must
ring
me
up
as
soon
as
you
can.
你必须尽快给我打电话。
②
please
write
to
me
as
soon
as
possible.
请尽早给我写信。
（2）、as
soon
as
引导时间状语从句，表示“一……就……”。如果主句用将来时或情态动词或祈使句，从句必须用一般现在时代替将来时。如：
i’ll
tell
him
the
news
as
soon
as
he
comes.
他一来我就告诉他那消息。
she
may
come
as
soon
as
she
finishes
the
work.
事情一做完她就可以来。

Answer 2

as和when、while的区别