在定语从句中 what是不可能出现的
如果在选择题中出现what肯定是错误
但定从中有种情况：
all that=all=what(而此处的what多是主语从句)
e.g.All that i've done is for you.
=All i've done is for you.
=What i've done is for you.
P.S.当that在定从中充当主语时,不可省
that和what在定语从句中有什么区别么
在定语从句中 what是不可能出现的
如果在选择题中出现what肯定是错误
但定从中有种情况：
all that=all=what(而此处的what多是主语从句)
e.g.All that i've done is for you.
=All i've done is for you.
=What i've done is for you.
P.S.当that在定从中充当主语时,不可省