18 Complete the sentences with the correct past forms of the verbs in brackets. 1) I lost (to lose) my keys while I was walking (to walk) to school.2) Hardly we(to finish) dinner when the doorbell(to ring3) He(to listen) to the radio while he(to prepare) breakfast.4) My father(to drive) at 70 km per hour when a policeman(to stop) him.5) When they(to come) to London, they(to visit) many museums and art galleries.6) Cindy(to break) her leg while she(to snowboard).7) After Angela(to lock) the door, the school bus(to arrive).8) He(to meet) a lot of friendly people before he(to move) to California.9) While we(to wait), we(to do)crossword puzzles.10) The students(to open) their exercise books and(to start) writing11) What(to do) when you(to hear) the news?12) While the children(to draw), their parents(to watch) TV.​