Question

as &which引导的定语从句的区分

Answer 1

1.
which引导的定语从句只能位于主句后，但as引导的从句可位于主句前、中、后。如：
david,
as
you
know,
is
a
photograopher.
戴维是个摄影师，你是知道的。(不可用which)
li
ming
is
late,
as
is
often
the
case.
李明迟到了，这事是经常发生的。(不可用which)
2.
as在定语从句中作主语时，从句谓语通常要有be或别的系动词，但which不受此限制。如：
li
ming
was
late,
which
(=and
this)
made
mr.
zhang
very
angry.
李明迟到了，这件事使张先生非常生气。(不可用as)
3.
as引导的定语从句只表示一个众所周知或意料之中的事，但which不受此限制。如：
he
married
her,
which
was
unexpected.
他和她结婚了，这是出乎意料的。(不可用as)
4.
as有“正如”之意，而which则意为“这(件事，一点)”，可用and
this/that/it来代替。
5.
as多用于固定搭配中：as
is
often
the
case(这是常有的事)，as
was
expected(不出所料)，as
often
happens(正如经常发生的那样)，as
is
known
to
all(众所周知)，as
has
been
said
before(如上所述)，as
is
mentioned
above(正如上面所提到的)等。
注：which代表整个句子，还可用于in
which
case,
at
which
point,
on
which
occasion等。如：
i
may
have
to
work
late,
in
which
case
i’ll
telephone
you.
我可能得晚点下班，那样我会给你打电话的。