完成體是動(dòng)詞的一種形式，表示動(dòng)作或狀態(tài)已經(jīng)完成，結(jié)構(gòu)是：主動(dòng)詞have的不同時(shí)態(tài)+-ed分詞。可以分為現(xiàn)在完成體和過(guò)去完成體。現(xiàn)在完成體大家比較熟悉了，那么今天小編就和大家一起學(xué)習(xí)我們不太熟悉的過(guò)去完成體~
過(guò)去完成體，顧名思義，就是表示在過(guò)去某一時(shí)間之前已經(jīng)發(fā)生或完成的動(dòng)作，也就是我們所說(shuō)的“過(guò)去的過(guò)去”。因此，它有“已完成”用法和“未完成”用法。結(jié)構(gòu)為：had+-ed分詞。
一、“已完成”：表示一個(gè)動(dòng)作或狀態(tài)在過(guò)去某時(shí)之前已經(jīng)完成或結(jié)束。
I had finished my homework when my friends came.我朋友來(lái)的時(shí)候，我就已經(jīng)完成家庭作業(yè)了。
My father had left for Beijing before I came home. 在我到家前，爸爸已經(jīng)離開(kāi)去北京了。
二、“未完成”：表示一個(gè)動(dòng)作或狀態(tài)在過(guò)去某時(shí)之前已經(jīng)開(kāi)始，一直延續(xù)到這一過(guò)去時(shí)間，而且到那時(shí)還未結(jié)束，仍有繼續(xù)下去的可能性。
Jack said that he had made much progress in English since he came here.
杰克說(shuō)自從他到這兒以后，英語(yǔ)已經(jīng)取得了很大進(jìn)步。
By six o’clock these workers had worked twelve hours. 到六點(diǎn)鐘時(shí)，這些工人已經(jīng)工作十二小時(shí)了。
三、連詞引導(dǎo)過(guò)去完成體用法：有些連詞引導(dǎo)的過(guò)去完成時(shí)可互換。
When I reached the station, the train had already left.
=I reached the station after the train had left.
=I didn’t reach the station until the train had left.
=The train had left before I reached the station.
在我到車站時(shí)，火車已經(jīng)走了。
四、過(guò)去完成體的虛擬用法：表示與過(guò)去事態(tài)相反的主觀設(shè)想。
1. 用于if, if only, as if引導(dǎo)的分句：
If you had worked hard, you would have passed the exam. 如果你努力學(xué)習(xí)的話，你就已經(jīng)通過(guò)考試了。
If I were you, I would not do it. 我要是你，就不做這事。
If only I had finished it before. 要是我之前完成了這件事就好了。
I felt as if I had been a bird in the sky.我感覺(jué)自己好似天空一只小鳥。
2. 用于I wish, I would rather引導(dǎo)的that從句：
I wished that I had knew the answer to the question before he asked me. 我希望在他問(wèn)我以前，我知道問(wèn)題的答案。
I would rather you had told me the truth. 我寧愿你跟我說(shuō)實(shí)話。
3. 用于expect, think, intend, mean, want, suppose等表示過(guò)去未曾實(shí)現(xiàn)的希望、打算或意圖。
I had intended to buy a present for you, but I forgot that. 我本打算給你買禮物的，但我忘了。
I had hoped that we could pass the exam, but we failed in the end. 我本希望我們都能通過(guò)考試，但最終我們失敗了。
因此，由上可知，比起現(xiàn)在完成體，過(guò)去完成體用法復(fù)雜，且具體“虛擬”的特殊用法，需要我們?cè)谄綍r(shí)使用中加以注意。
