1.“疑问代词 + ever”可引导两种类型的从句,即让步状语从句和名词性从句(主语从句、宾语从句).
(1)引导让步状语从句.此时 whatever / whoever / whichever 分别等于“ no matter + what / who / which”.例如：
Whatever happened,he wouldn't say a word.= No matter what happened,he wouldn't say a word.
Whoever says so,it is wrong.= No matter who says so,it is wrong.
Whichever dictionary you (may) take,you will have to pay at least 20 dollars.= No matter which dictionary you (may) take,you will have to pay at least 20 dollars.
注意：这类从句中应用一般现在时表将来,从句中也常用情态动词 may / might .
(2)引导名词性从句.例如：
Whoever smokes here will be punished.(主语从句)
Beggars will eat whatever they are given.(宾语从句)
Whichever he likes will be given to him.(主语从句)
You may invite whoever / whomever you like.(常用 whoever 代替 whomever)
此时它们都不能换成“ no matter + 疑问词”的形式,但 whoever 等于 anyone who,whatever 等于 anything that.
2.“疑问副词 +ever ”：wherever / whenever / however 一般只能引导一种类型的从句,即让步状语从句,此时它们分别等于“ no matter + where / when / how ”.例如：
Wherever he goes (may go).I'll follow him.= No matter where he goes (may go),I'll follow him.
Whenever I wisited him,he was always busy working.= No matter when I visited him,he was always busy working.
However late he is,his mother will wait for him to have dinner together.= No matter how late he is,his mother will wait for him to have dinner together.
注意：当 however 用作连接副词时也可引导名词性从句,而 whenever/ wherever 则不能引导名词性从句.例如：
I'll give you however much money you need.(宾语从句,此时 however 不能改成 no matter how ).
3.另外,whatever / whichever / whoever 与 whenever / wherever / however 分别可相当于 what / which / who 与 when / where / how 的强调式,引起的特殊疑问句往往是简单句,与原疑问词的意思、用法完全相同,只是表达的语气更为强烈,翻译时可加上“到底；究竟”等.例如：
What(ever) are you doing 你(到底)在干什么?
Which(ever) do you want to buy 你(究竟)要买哪一个?
Who(ever) told you such a foolish story?(究竟)是谁讲给你这么蠢的事?
When(ever) can I enjoy a long vacation?(究竟)什么时候才能给我放个长假呢?
Where(ever) did you leave your dictionary?你(究竟)把词典放哪儿了?
How(ever) did you collect so much money?你(到底)是怎样筹到这么多钱的?