Ответ:
1.Where were you, I was, I rang, nobody answered, I was, I was reading, did not hear.
2. What were you doing, I was working, I was, I did not see.
3.Nina celebrated, there were, I came, somebody was playing, two or three pairs were dancing.
4.Somebody is playing.
5.I like.
6.I looked, it was raining, people were hurrying.
7.What were you doing, I was having.
8.I came, I saw, were sitting, father was reading, who lives.
9.I was working.
10.It was raining.
11.Where is your sister, she is, she is doing.
12.He is brushing, he cleans.
13.She is sleeping.
14.You are talking, you never talk.
15.My mother is sitting, I am setting.