1、当what用作连接代词，引导名词性从句时，可引导主语从句、表语从句和宾语从句（不可引导同位语从句）；它本身在句中充当主语、宾语或表语。[解题过程]注意what 和that引导名词性从句的差别 ：一、当what用作连接代词，引导名词性从句时，可引导主语从句、表语从句和宾语从句（不可引导同位语从句）；它本身在句中充当主语、宾语或表语。1、 what表示“所以……的（事）”的意思，相当于“the thing(s) that……”、“all that……”、“that which……”、“everything that……”等。例如：（1） Leave it with me and I’
2、ll see what I can do.(what引导宾语从句，并作do的宾语。)（2） What you have done might do harm to other people. (what引导主语从句，并在从句中作宾语。)（3） What he said at the meeting astonished everybody present. (what引导主语从句，并在从句中作宾语。)（4） What is most important in life isn’t money. (what引导主语从句，并在从句中作主语。)（5） But wait till yo
3、u see what we’ll make for you to your own measure. (what 引导宾语从句，并在从句中作宾语。)（6） What he wanted to see was an end to all the armies of the world. (what 引导主语从句，并在从句中作宾语。)2、 what 表示“所……的（人）”的意思，相当于“the person that……”等。例如：（1） He is not what he used to be. (what 引导表语从句，并在从句中作表语。)（2） She is no long
4、er what she was five years ago. (what 引导表语从句，并在从句中作表语。)二、that 当that用作连接词，引导名词性从句时，可引导主语从句、表语从句、宾语从句和同位语从句，that 在从句中既不充当任何成分，也无实际意义，仅起着连接句子的作用。和般不可省略（宾语从句除外）。若从句置于句子后面，代词it作形式主语。例如：（1） It worried her a bit that her hair was turning grey. (that引导主语从句)。（2） It is a fact that Chinese is accepted
5、as an international language. (that引导主语从句)（3） Can you believe (that) in such a rich country there should be so many poor people?( that引导宾语从句)（4） Tom felt that he knew everybody’s business better than they knew it themselves.( that引导宾语从句)（5） We heard the news that our team had won.. (that引导同位
6、语从句)（6） Another problem is that good soil is gradually lost. (that引导表语从句)（7） But the truth is that everyone should take care of disabled people, not just the government. (that引导表语从句)
