Question

while与when的用法

Answer 1

when
当什么时
可表瞬间
事情可同时
或者先后发生
例子
it
was
snowing
when
we
got
to
the
airport
我们到机场时
天在下雪(先后顺序)
while
用于相伴发生的
同时进行
例子
some
students
were
reading
while
others
were
writing
有些学生在读书
有些在写.
①when是at
or
during
the
time
that,
既指时间点，也可指一段时间，while是during
the
time
that，只指一段时间，因此when引导的时间状语从句中的动词可以是终止性动词，也可以是延续性动词，而while从句中的动词必须是延续性动词。
②when
说明从句的动作和主句的动作可以是同时，也可以是先后发生；while
则强调主句的动作在从句动作的发生的过程中或主从句两个动作同时发生。
③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.
④when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

Answer 2

Answer 3