what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；它本身在从句中充当主语、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；everything that；等。例如：1)Leave it with me and Ill 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)2.What 表示“所的(人)”意思，相当于“the person that”等。例如：1)He is not what he used to be.他已不是从前的他了。(what引导表语从句并在从句中作表语)2)She is no longer what she was five years ago.(what引导表语从句并在从句中作表语)
