whenever & no matter when有什么不同？

Question

语法填空什么时候只能填WHENEVER不能填NO MATTER WHEN？
什么时候只能填NO MATTER WHEN不能填WHENEVER？？

Answer 1

是词性的问题whenever可以conj.和n. no matter when一般做adv.关键看句子的构成。

Answer 2

引导让步状语从句时候可以互换；但是引导名词性从句时候只能用
whatever;
whomever
whenever
you
leave,
please
tell
me.=no
matter
when
you
leave,
please
tell
me
whatever
you
do,
do
it
well.
=no
matter
what
you
do
,
do
it
well.
it
is
unwise
to
give
whatever
the
kids
want.
不能替换。