现在完成时( The Present Perfect Tense)是过去的动作或状态持续到现在，对现在造成的影响或结果，可能持续发生下去。在英语时态中，"时"指动作发生的时间，"态"指动作的样子和状态。
完成时态的构成分为两部分:
一是助动词,用have/has表示"时"；
二是实义动词的过去分词，用过去分词来表示动作的"态"，以表明该动作已经完成，而且对现在有一定的影响。
结构为：主语 助动词(have/has) 动词的过去分词(done)
现在完成时态常常和这样一些短语连用：Since, ever since, recently, just, of late, so far, up to now, by now, in/over the past / last six years, for two days, the first / best/worst /only…
例句：
This is the first time that I have been to Shanghai.
This is the best place that I’ve ever visited.
Over the years he’s become more and more polite.
This is the only English book I’ve ever bought.
We have learnt more than 3000 words up to now.
