1.While we __________ (wait) for the bus,a girl __________ (run) up to us.
2.I __________ (telephone) a friend when Bob __________ (come) in.
3.Jim __________ (jump) on the bus as it __________ (move) away.
4.We __________ (test) the new machine when the electricity __________ (go) off.
5.She __________ (not want) to stay in bed while the others ________________ (all,work) in the fields.
6.While mother ________ (put) Cathy to bed,the door bell ________ (ring).
7.As I __________ (walk) in the park,it __________ (begin) to rain.
8.Even when she ___________ (be) a child she ________________ (always,think) of becoming a ballerina (芭蕾舞演員).
9.It was quite late at night.George __________ (read) and Amy __________ (play) her needle when they __________ (hear) a knock at the door.
一定要正確,