英语中的名词性从句的分类及详细介绍

引导名词性从句的连接词可分为三类：
连接词：that,whether,if
不充当从句的任何成分）
连接代词：what,
whatever,
who,
whoever,
whom(ever),
whose(ever),
which(ever).
连接副词：when,
where,
how,
why
,how
many,how
much,等,代词在从句中可以作主语,宾语,表语,定语,而副词在从句中作状语
eg.What
you
said
sounds
reasonable.
Whatever
you
said
is
right.(这两句中都是主语从句)
eg:He
wants
to
know
whether/if
we
can
help
him.(动词后宾语从句用这两个是否都可以)
They
are
talking
about
whether
we
will
go
for
a
picnic.(介词后宾语从句,只用这一个是否)
eg:What
I
can't
understand
is
why
he
left
without
saying
a
word.(why引导的是表语从句)
eg:
I
have
no
idea
why
he
left
without
saying
a
word
.(why引导的同位语从句,即对前一个名词的解释或说明)