Question: Is there a difference between saying I have done my homework and I did my homework?

The first sentence is in Present Perfect (have + 3rd form verb) and the second is in Past Simple (2nd form verb). The difference between them is mainly connected with time.

Present Perfect is chiefly used when we are talking about something in the past that is connected to the present, often because it didn’t happen too long ago. We often use the words just, recently and already with this tense.

• I haven’t yet eaten breakfast. I’ve just woken up!

• I haven’t written my report yet, but I’ve already collected all the data.

We also use this tense to talk about undefined times in the past, often with the word ever, or for unfinished time periods (e.g. this year)

• Have you ever been to Paris?

• It’s nearly noon. Has anyone seen Mark today?

We use past tense at a specified, finished time in the past.

• I visited that museum three times last year.

• I went to Paris once when I was a child.