请问下面这句话里这样用不定式正确吗

一句要表达的汉语是：对于情态动词 Can，could，may，我们一定要确定什么时候用哪一个。

我看一句英文是： For can，could and may， let's be really sure when to use which one.

英文里的to use是不定式吗？如是不定式，那是否用在了谓语的位置上，是否就不对？如错误，正确英文应如何表达？

疑问词+to do不定式，其实是名词性疑问分句的一种简略。when to use which one = when we should use which one. 即句子省略了主语+情态动词，把情态动词后的不定式改为带to的不定式。又如：

I don't know what to say.

= I don't know what I can/should say.

He didn't say when to come.

= He didn't say when he would come.

曹荣禄 -

擅长：动词用法,句法问题 | 采纳率 82% | 回答于 2021-02-21 19:29

其它 0 个回答