what does he like doing?为什么用doing

问题描述:

what does he like doing?为什么用doing
还一个题 he does his homework every day?为啥用does
what is your sister doing?she's reading 我想知道为神魔不用does

第一个用doing,是因为固定搭配like doing Sth.
第二个用does,是因为第三人称单数,每天做什么事情,经常做什么事情,都要用为第三人称单数
第三个不用does,是因为要表达的是她现在在做的事情,要用现在进行时