1) was cooking, went, burnt.
2) hurt, was skating
3) entered, were feeding
4) was visiting, bought
5) started, were bathing
6) was having
7) came, was doing
8) What did you do...
9) was going
10) were sleeping, went
11) was reading, came, sat
12) was walking, passed
13) was looking, saw
14) were answering, entered
15) were drinking, came
16) was walking, passed
17) was thinking, fell
18) listened
19) entered, was writing, were copying
20) were getting, began