现在完成定义:现在完成进行时表示某动作从过去某个时间开始,一直延续到现在,并且还有可能持续下去。如:
Those cats have been screaming for hours.
那些猫叫了半天了。
We have been waiting for him for two hours.
我们等他等了两个小时。
The dollar has been climbing steadily all week.
整个星期美元一直在稳步增值。
构成:主语 + have / has + 过去分词 + 其他(当主语是第三人称单数时用has,其余人称用have。过去分词:规则动词的过去分词构成与动词过去式相同;不规则动词需要特殊记忆。)
否定式:主语 + haven’t / hasn’t + 过去分词 + 其他
疑问式:Have / Has + 主语 + 过去分词 + 其他?
简略答语:Yes, 主语 + have / has.(肯定)
No, 主语 + haven’t / hasn’t.(否定)
现在完成时的含义之一是过去完成的动作对现在仍有影响,用以下四大标志词可以表达这种含义:
一、以already, just和yet为标志
already, just和yet表示到现在为止动作或状态已经、刚刚或还没有发生。
He has already got her help.
他已得到她的帮助。
He has just seen the film.
他刚刚看过这场电影。
He hasn’t come back yet.
他还没有回来。
二、ever和never为标志
ever和never表示到现在为止动作或状态曾经或从来没有发生过。
This is the best film I have ever seen.
这是我曾经看过的最好的一部电影。
He has never been to Beijing.
他从没有到过北京。
三、以动作发生的次数为标志若某一动作到现在为止已经发生了若干次,则要使用现在完成时。
He says he has been to the USA three times.
他说他已经去过美国三次了。
四、以so far为标志
so far往往表示到目前为止动作或状态已经发生。
He has got to Beijing so far.
到目前为止他已到了北京。
She has passed the exam so far.
到目前为止她已经通过了考试。
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