We use "which" as a determiner to ask a question about a specific group of people or things: 我們用限定詞“which”問(wèn)特定的一組人或物：
Which restaurant did you go to?
Which countries in South America have you visited?
When we are asking a general question we use "what" as a determiner:
用“what”問(wèn)較為普遍的問(wèn)題：
What films do you like?
What university did you go to?
