Hey everyone, this is my first post.
This question may sound a little stupid. I can't always decide whether I have got to write "have" or "did".
For example:
"Have you done your homework?" or..."Did you do your homework?"
Wich one of both is correct?
How do I can always recognize whether I have to write "have" or "did"?

This year I'm going to sit for the FCE and if I dont solve this problem I'll really get into trouble Emotion: stick out tongue
Have/has + past participle = [url=http://grammar.ccc.commnet.edu/grammar/tenses/present_perfect.htm ] PRESENT PERFECT[/url]
Did + infinitive = [url=http://grammar.ccc.commnet.edu/grammar/tenses/simple_past.htm ]PAST SIMPLE[/url].
See also these links:

[url=http://www.englishpage.com/verbpage/presentperfect.html ]Present Perfect[/url]

[url=http://www.englishpage.com/verbpage/simplepast.html ]Past Simple[/url]