一:用正确时态填空
1.As my father___(leave)the house,the postman_____(arrive).
2.Tom____(work)in the garden while I___(sit)in the sun.
3.As I___(walk)down the street ,I___(meet)Charile.
4.While he___(read)the letter,he___(hear)a knock at the door.
5.While mother___(prepare)lunch,Janet___(set)the table
6.She___(drop)the tray when I___(speak)to her