was doing是過去進(jìn)行時,表示過去正在發(fā)生.例如：She was washing when her son came in.（她兒子進(jìn)來時她正在洗衣服.）
had been doing是過去完成進(jìn)行時,基本相當(dāng)于過去完成時,但可以強(qiáng)調(diào)動作延續(xù).例如：They had been playing chess for the whole afternoon when their father went back from work.（他們的父親下班回來時,他們已經(jīng)下了一下午棋了.）
had been done是過去完成時的被動式,和前兩個沒有關(guān)系.例如：When the firemen got to the building,the fire had been put out.（等消防員感到那棟大樓的時候,火已經(jīng)被撲滅了.）