1.When the bell rang the children (to run) into the classroom and (to take) their seats.
2. When I
opened the door, the lesson (to begin) and the teacher (to explain) something to the class
3.Before we (to take) the boy to the theatre he (never to see) a play.
4.I (to clean) the carper when the dog (to come) and (to shake) himself
5.By the time we (to arrive) the party (to finish)
6.-When you (to do) when I (to call) you?- I ( to cook)