1 I've already done my homework.
2 did
3 He has just come home
4 came
5 When did you go to the park
6 was
7 I haven't seen him...
8 Where did you meet her?
9 The sun hasn't risen yet.
10 left
11 How did it happen?
12 When did you open the door? I opened it ten minutes ago
13 Has he ever been to Paris? yes. He was there last year.