Present vs. Past Tenses in asking questions

[Sylphidae]

A.) Did he close the window?
B.) Does he close the window?

Are they both correct? When should I use A? B?

[Sunny]

You use A. when you want to ask something about the past. Maybe you told somebody to close the window, but you don't know, if he actually did it. Then you ask somebody else: "Did he close the window?"

B. - you wouldn't use that at all, I think. It would have the meaning of something that happens regularly, since it is the Simple Present tense. (Nobody closes a window regularly :) ) But you would probably ask: "Does he go to school?" or "Does he work?"

As for the window, you could say: "Is he closing the window?", if you want to know what this person is doing at the moment - using the Present Progressive.

:)