3.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.