英语疑问词 “what” 和 “which” 用来引导问句，但由它们引导的问句之间有一个根本的区别。哪一个词用来引导有选择的疑问句？哪一个词引导的问句，其答案不受任何限制？

怎样区分 what 和 which?

1 What is used to ask a question which has a lot of possible answers.

用 “what” 引导的疑问句的回答没有限制，有很多种可能。What do you want to eat for lunch?

Here, there are no choices to limit your reply. You could choose anything you want.

这个问题的回答没有限制，可以根据自己的喜好作答。

2 We use which when we have options to choose from.

当提问有选择时，用 “which” 引导疑问句。

So, here we have two choices – a sandwich and a melon. So I can say:

比如：我有两个选择，选择一：三明治，选择二：瓜 。这时就可以问：

Which do you want to eat? The sandwich or the melon?