what you say is quite true.中的what等于that which.若换成that which

what you say is quite true.中的what等于that which.若换成that which what you say is true.中的主语what you say 可换成what you said吗 that is what i say.这里的what是引导的表语从句吗?能换成which吗. (what;that;which) WHICH THAT WHAT what,which,that 区别 Who doubts --------it is true?A.that B.if C.which D.what It is true we are aliens.A.which B.what C.who D.that choose the one that is right for you 中的that为什么不能换成which what is that which you have never seen,heard of felt which n there is nothing ___ I want to say.A.which B.what C.that 选哪个 Did you say that what he said was true