1.As my father was leaving (leave)the house ,the postman arrived(arrive).
2.Tom was working (work)in the garden while I was sitting(sit) in the sun.
3.As I was walking(walk) down the street ,I met(meet) Charlie.
4.While hewas reading(read) the letter ,he heard(hear) a knock at the door.
5.While mother was preparing(prepare) lunch ,Janet set(set) the table.
6.She dropped (drop) the tray when I was speaking(speak) to her.
有任何疑问也欢迎提问,