小升初必備語法：過去完成時

1) 概念：表示過去的過去

　　----|-------|-----|---->其構(gòu)成是had +過去分詞構(gòu)成。

　　那時以前　 那時　現(xiàn)在

　　2) 用法

　　a.　在told, said, knew, heard, thought等動詞后的賓語從句。

　　She said (that) she had never been to Paris.

　　b. 狀語從句

　　在過去不同時間發(fā)生的兩個動作中，發(fā)生在先，用過去完成時;發(fā)生在后，用一般過去時。

　　When the police arrived, the thieves had run away.

　　c. 表示意向的動詞，如hope, wish, expect, think, intend, mean, suppose等，用過去完成時表示"原本…，未能…"

　　We had hoped that you would come, but you didn't.

　　3)　過去完成時的時間狀語before, by, until , when, after, once, as soon as。

　　He said that he had learned some English before.

　　By the time he was twelve, Edison had began to make a living by himself.

　　Tom was disappointed that most of the guests had left when he arrived at the party.

　　典型例題

　　The students ___ busily when Miss Brown went to get a book she ___ in the office.

　　A. had written, left　B，were writing, has left　 C. had written, had left　D. were writing, had left

　　答案D. "把書忘在辦公室"發(fā)生在"去取書"這一過去的動作之前，因此"忘了書"這一動作發(fā)生在過去的過去，用過去完成時。句中when表示的是時間的一點(diǎn)，表示在"同學(xué)們正忙于……"這一背景下，when所引導(dǎo)的動作發(fā)生。因此

　　前一句應(yīng)用過去進(jìn)行時。

　　注意：　had no … when　　　　　還沒等…… 就……

　　had no sooner… than　　剛…… 就……

　　He had no sooner bought the car than he sold it.