過去完成時常用的時間狀語有：

　　1. by the end of last+時間段. By the end of last term, we had learned 5000 new words.

　　到上學(xué)期末，我們已經(jīng)學(xué)了5000個新詞。

　　2. By the time sb. +動詞過去式如： The bus had already left by the time I got there.

　　我到那兒時，公共汽車已經(jīng)開走了。

　　3.By (the time of)+時間段

　　By the time of last year ,we had built two bridges.

　　到去年為止，我們已經(jīng)建了兩座橋。