1) It was 8 o'clock when we decided to have some tea.
2) We were having supper when our visitors rang at the door.
3) They were in the stadium when the football match began.
4) The teacher was sitting at her desk when we finished writing the test.
5) They were reading an article when they heard the music.
6) She was washing up when the film began.
7) We were skiing when started snowing.
8) I was playing chess when mother said that dinner was ready.