1)两个动作如按顺序发生,又不强调先后,或用then,and,but 等连词时,多用一般过去时。例如:
When she saw the mouse,she screamed. 她看到老鼠,就叫了起来。
My aunt gave me a hat and I lost it. 姑妈给了我一顶帽子,我把它丢了。
2 ) 两个动作相继发生,可用一般过去时;如第一个动作需要若干时间完成,用过去完成时。例如:
When I heard the news, I was very excited.
3)叙述历史事实,可不用过去完成时,而只用一般过去时。例如:
Our teacher told us that Columbus discovered America in 1492.