一、名词性从句的种类
名词性从句包括主语从句、宾语从句、表语从句、同位语从句。
二、引导名词性从句的连接词
1．连接代词：who, whose, whom, what, which有词义，在从句中担任成分，如主语、表语、宾语或定语等。
It has not been decided yet when we will leave.
We are worrying about what we should do next.
2．连接副词：when, where, why, how有词义，在从句中担任成分，作状语。
It makes no difference where we shall have the meeting.
Scientists study how human brains work to make computers.(2012·四川高考)
3．连接词： whether, if, as if, if (whether), as if虽有词义，但在从句中不充当任何成分，只起连接作用；that无词义，在从句中也不充当任何成分，只起连接作用，有时可省略。
My suggestion is that we (should) have a discussion about this matter.
The question whether we need more time to do the work hasn’t been discussed.
