在英語語法16多種時態(tài)中，過去將來完成時是用的相對較少的一種時態(tài)，它表示從過去觀點看將來某時某刻某個動作已經(jīng)完成的一種狀態(tài)。通常主要用于轉述方面，即用于間接引語中。
過去將來完成時基本形式：should / would have done sth.例句：
1. I would have left the building before the murder took place.
在謀殺發(fā)生的時候，我就已經(jīng)離開了這座樓。

2. I thought you would have left by this time.
我想你這會兒已經(jīng)走了。

3. I would have eaten the breakfast before my friends came in.
在我朋友進來的時候，我已經(jīng)吃完早飯了。

4. I thought you would have done your homework as soon as possible.
我認為你應該盡快完成作業(yè)。

5. I would have finished this project before my boss called me.
在老板給我打電話的時候，我就已經(jīng)完成了這個項目。

6. I thought you would have fed this litter cat.
我認為你應該喂養(yǎng)這只小貓。