Another way to present it: 1. "Since I have done my homework, I will go to the movies". The reference point is "now", so present perfect. 2. "Since I had done my homework, I went to the movies". The reference point is in the past, so past perfect.

"Have done" is called present perfect tense and "Had done" is called past perfect tense. Here are examples: "I have lived here for there months." : Meaning "I" started living here three months ago, and continue until now. "He have done five 20-page term papers." : Meaning he did five 20-page term papers so far. ( the number of paper is emphasized); this sentence also describes an action that happened before NOW without exact date. "I had been there when she came." : Meaning I was there BEFORE she did. So, tips are: 1, "have done" doesn't require a certain date an action happened. It either shows the recently done action or emphasizes the result of an action. 2, "had done" requires the certain date because it describes an action happened BEFORE that date. Hope this helps!

I'm not sure how to explain this but I'll try. "I have done" is present perfect tense and is used to describe something one has done in the recent past but speaking in the present. example: "I have done my homework and so I will go to the movies". "I had done" is past perfect tense and is used to describe something that one has done in the past when speaking about the past. example: "I had left work and so then I went to the store".

thanks alot ,that was so useful