1) They were climbing the mountain when he fell off.

2) My dad was waiting for me at 4 pm yesterday.

3) You were having a shower when the telephone rang.

4) I was going home when I had a puncture.

5) The kids were playing in the sands yesterday.

6) You were putting on some warm clothes when I came in.

7) Tom was riding a bike when I saw him.

8) They were cleaning the windows when it started to rain.

9) He was taking notes from 2 to 4 yesterday.

10) Mum was ironing the laundry yesterday afternoon.

11) The students were studying Math yesterday.

12) I was staying with my friend last week.