定语从句引导词what和that的区别,麻烦详细一点

定语从句引导词即连词中没有what.有that,who,which,whose,whom,where 等.
1当先行词为人时用who或that .如：He is the man that /who likes playing basketball.
2当先行词为物时用which 或that.如：The book which /that I bought yesteday is very interesting.
总之,what 引导的是宾语从句而不是定语从句.如：I don't know what I should do next.

这个你初三的吗？如果是的话，复习书上都有的。

I heard he would come here later on.
that引导的宾语从句（在非正式场合that可以省略）that 没有任何含义。，
I want to know what his favourite subject is.
what 是有含义的，