過去完成時

　　1 、過去完成時是一個相對時態，表示過去的過去，只有在兩個過去發生的動作相比較時才可顯示出來。

　　e.g. As soon as we got to the station, the train had left.

　　注：主從句表達的動作緊接時，即兩動作發生的時間沒有明顯時間上的懸殊或空檔時，主從句都可用一般過去時。

　　e.g. Where did your brother study before he joined the army?

　　2 、過去完成時可表示截止過去某一時間動作的總或動作的結束。

　　e.g. By the end of last month. We had reviewed four books

　　By eight o`clock, he had finished his homework.

　　與這個時態連用的時間狀語常有：

　　by 1985, by eight o`clock, by then, by the end of last month, by the time when, when, as soon as, before 等連詞引導的時間狀語從句，表示主句動作結束的時間。