文档介绍：现在完成时与过去一般时
从过去一直延续到现在的动作和状态。
常用的时间状语有：since, （可用作介词和连词）for
注意：主句的谓语动词一般是延续性的动词，如果是否定形式，主句的谓语动词可用瞬间动词，否则，不能用瞬间动词。
I I came here after I had finished middle school.(两个动作有间隔,强调先后概念)
2) I waited till I saw him.
I waited till I had seen him. (这两个句子差不多,过去完成时更普遍)
3) We hoped he would come.(我们希望他来)
We had hoped he would come.(我们本希望他来的)
4) I don't think he sang as well as he once did.(指具体一次)
I don't think he sang as well as he had once done.(泛指以前,现在可能不唱了)
5) Before I came here, I was a soldier.(我来此以前在当兵)
Before I came here, I had been a soldier.(我来此以前,曾当过兵)
6) Jim said he didn't know he was so strong.(表示Jim在说话时仍很结实) Jim said he didn't know he had been so strong.(表示在Jim说话之前曾结实过)
7) They were friends from many years.(表示现在还是朋友)
They had been friends for many years.(意味这友谊结束了)
8) He did the work at 6.(强调时间)
He had done the work at 6. (6点工作已做完)
9) I learned French during my holiday.(强调学了)
I had learned French during my holiday. (强调学会了)
10) When she sang she sat down.(表示唱着坐下)
When she had sung she sat down.(表示唱完坐下)
11) I went to bed when I did my homework.(不明确)
I went to bed when I had done my homework.(作业做完)
12) I have lived here since I was a child.(从我长大***)
I have lived here since I had a child.(从我孩提时)
5. 过去进行时与过去一般时
1) I read a book yesterday. (书已看完)
I was reading a book yesterday.(书尚未看完)
2) The guests arrived.(客人已到)
The guests were arriving.(客人陆续到达)
3) He wo