___David says sounds right to Helen.That's why she has made up her mind not to leave him ___happens

这两个单词意思都一样,都是无论什么的意思
但no matter what只能放在句首,在句中,只能用whatever
"no matter +疑问词" 或"疑问词+后缀ever" .
例如：
No matter what happened,he would not mind.=Whatever happened,he would not mind.
不管发生什么,他不在意.
替换：
no matter what = whatever
no matter who = whoever
no matter when = whenever
no matter where = wherever
no matter which = whichever
no matter how = however
注意：no matter 不能引导主语从句和宾语从句.
(错）No matter what you say is of no use now.（对）Whatever you say is of no use now.你现在说什么也没用了.（Whatever you say是主语从句）
（错）Prisoners have to eat no matter what they're given.
（对）Prisoners have to eat whatever they're given.囚犯们只能给什么吃什么.你没看我回答的后面说的吗？no matter 不能引导主语从句和宾语从句。 (错）No matter what you say is of no use now.（对）Whatever you say is of no use now. 你现在说什么也没用了。（Whatever you say是主语从句） ___David says sounds right to Helen.这个句子的意思是无论大卫说什么，海伦都觉得对。这是个主语从句。所以不能用NO matter。