牛津高中英語語法復習：動詞時態

2.---i'm sorry to keep you waiting.
　---oh, not at all. i ___ here only a few minutes.
a. have been　 b. had been　 c. was　d. will be
　 答案a. 等待的動作由過去開始，持續到現在，應用現在完成時。
15 過去完成時
1） 概念：表示過去的過去
----|-------|-----|---->其構成是had +過去分詞構成。
那時以前　 那時　現在　　　　　　
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
　　 在過去不同時間發生的兩個動作中，發生在先，用過去完成時；發生在后，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"發生在"去取書"這一過去的動作之前，因此"忘了書"這一動作發生在過去的過去，用過去完成時。句中 when表示的是時間的一點，表示在"同學們正忙于……"這一背景下，when所引導的動作發生。因此
前一句應用過去進行時。
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.
16 用一般過去時代替完成時
1)　兩個動作如按順序發生，又不強調先后，或用then，and，but 等連詞時，多用一般過去時。
　　 when she saw the mouse， she screamed.
　　 my aunt gave me a hat and i lost it.
2 ) 兩個動作相繼發生，可用一般過去時；如第一個動作需要若干時間完成，用過去完成時。
　　 when i heard the news, i was very excited.
3)　敘述歷史事實，可不用過去完成時，而只用一般過去時。
　　 our teacher told us that columbus discovered america in 1492.
17 將來完成時
　1) 構成will / be going to do sth.
　2) 概念　
　　a. 狀態完成：表示某事繼續到將來某一時為止一直有的狀態。
　　b. 動作完成：表示將來某一時或另一個將來的動作之前，已經完成的動作或一獲得的經驗。
　　　they will have been married for 20 years by then.
　　　you will have reached shanghai by this time tomorrow.
18 現在進行時