Ответ:
1) were they taking the exam?
2) when was he working there?
3) were you making a dinner?
4) were they drinking coffee when you arrived?
5) when were we sleep?
6) they were studing last night
7) we were talking when the accident happened
8) he wasn't exerciseing enough
9) was I talking too much?
10) it wasn't snowing
11) how were they feeling?
12) they wasn't talking
13)Where was I staying?
14)Why was he studing on a Saturday night?
15)I was going to school when you saw me
16)Were you sleeping at 6am?
17)She was working when I called
18)We weren't leaving when you called
19)I wasn't staying in a hotel
20)Were we making too much noise?