1) 兩個動作如按順序發(fā)生,又不強調先后,或用then,and,but 等連詞時,多用一般過去時。
When she saw the mouse,she screamed.
My aunt gave me a hat and I lost it.
2 ) 兩個動作相繼發(fā)生,可用一般過去時;如第一個動作需要若干時間完成,用過去完成時。
When I heard the news, I was very excited.
3) 敘述歷史事實,可不用過去完成時,而只用一般過去時。
Our teacher told us that Columbus discovered America in 1492.