grammar动词时态(编辑修改稿)

grammar动词时态(编辑修改稿)内容摘要：

 A. was B. have been C. came D. am ing  答案 B. This is the first time 后面所加从句应为现在完成时，故选 B。 22  (2) Have you ____ been to our town before?  No, it39。 s the first time I ___ here.  A. even, e B. even, have e C. ever, e D. ever, have e  答案 D. ever意为曾经或无论何时，反意词为 never，此两词常用于完成时。 This is the largest fish I have ever seen. It is / was the first time +thatclause 的句型中，从句要用完成时。  注意：非延续性动词的否定形式可以与表示延续时间的状语连用。 即动作不发生的状态是可以持续的。  （错） I have received his letter for a month.  （对） I haven39。 t received his letter for almost a month. 23 比较 since和 for  Since 用来说明动作起始时间， for用来说明动作延续时间长度。  I have lived here for more than twenty years.  I have lived here since I was born..  My aunt has worked in a clinic since 1949.  Some new oilfields have been opened up since 1976.  I have known Xiao Li since she was a little girl.  My brother has been in the Youth League for two years.  I have not heard from my uncle for a long time. 24  注意：并非有 for 作为时间状语的句子都用现在完成时。  I worked here for more than twenty years.  (我现在已不在这里工作。 )  I have worked here for many years.  (现在我仍在这里工作。 ) 25  小窍门： 当现在完成时 +一段时间，这一结构中，我们用下面的公式转化，很容易就能排除非延续动词在完成时中的误使。  1) (对 ) Tom has studied Russian for three years.  = Tom began to study Russian three years ago, and is still studying it now.  2) (错 ) Harry has got married for six years.  = Harry began to get married six years ago, and is still getting married now.  显然，第二句不对，它应改为 Harry got married six years ago. 或 Harry has been married for six years. 26 since的四种用法  1) since +过去一个时间点 (如具体的年、月、日期、钟点、 1980, last month, half past six)。  I have been here since 1989.   2) since +一段时间 + ago  I have been here since five months ago. 27  3) since +从句  Great changes have taken place since you left.  Considerable time has elapsed since we have been here.  4) It is +一段时间 + since从句  It is two years since I became a postgraduate student. 28 延续动词与瞬间动词  1) 用于完成时的区别  延续动词表示经验、经历； 瞬间动词表示行为的结 果，不能与表示段的时间状语连用。  He has pleted the work. 他已完成了那项工作。 (表结果 )  I39。 ve known him since then. 我从那时起就认识他了。 (表经历 ) 29  2) 用于 till / until从句的差异  延续动词用于肯定句，表示 做 …… 直到 …… 瞬间动词用于否定句，表示 到 …… ，才 ……  He didn39。 t e back until ten o39。 clock.  他到 10 点才回来。  He slept until ten o39。 clock.  他一直睡到 10点。 30  典型例题  1. You don39。 t need to describe her. I ___ her several times.  A. had met B. have met C. met D. meet  答案 B. 首先本题后句强调对现在的影响，我知道。