what 和 whatever 都可以引导名词性从句,区别在于whatever=anything which 隐含了一个“任何（any）”
试比较：
you can have anything you want if you work hard.
=you can have whatever you want if you work hard.这里用what语法上也没错,但意思表示上不同.
以此类推.who和whoever同理.
when引导时间状语“当……发生时”
where 地点状语“在什么地方……,在……发生”
which 表示选择,侧重“哪一个”
加油.