1.
现在完成时 (1)现在完成时用来表示对目前状况仍有影响的,刚刚完成的动作(常与yet,already,just连用),或者过去某一时刻发生的,持续到现在的情况(常与for,since连用)。例如: 1)I have just finished my homework. 2)Mary has been ill for three days. (2)常与现在完成时连用的时间状语有:since, for, during, over等引导出的短语;副词already, yet, just, ever, now, before, often, lately, recently等;状语词组this week (morning, month, year), so far, up to now, many times, up to the present等。例如: 1)I haven’t been there for five years. 2)So far, she hasn’t enjoyed the summer vacation. 3)There have been a lot of changes since 1978. (3)完成时态可用在下列结构中: This (That, It) is (was) the first (second…) time +
定语从句;This (That, It) is (was) the only (last) + n +定语从句;This (That, It) is (was) +形容词最高级+ n +定语从句。如果主句的谓语动词是
一般现在时,从句的谓语动词通常用现在完成时;如果主句谓语动词是
一般过去时,从句谓语动词通常用
过去完成时。例如: (1)This is one of the rarest questions that have ever been raised at such a meeting. (2)There was a knock at the door. It was the second time someone had interrupted me that evening. already(已经)【通常不放在句尾】,yet(已经),for,before,ever(曾经),never(从未),so far(到目前为止),since(从......时候) for+一段时间 如:one year(一年) ,two month(两个月)而since+时间点 如:one year ago(一年之前) 表示的是一个具体的时间,例如今天是09年8月1日,它指的就是具体的08年8月1日。 *完成时的定语从句 since引导的定语从句主句用完成时,后面的从句一定要用一般过去时。例如:He hadn't been back there since he finished high school. 从他中学毕业后他就没有回去过那里。 since后面的句子没有had,直接用
过去式,而主句则用的过去完成时。
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