单词present perfect
na.: 【语】现在完成式(的)；现在完成式的动词
网络: 现在完成时；现在完成时态；现在完成时态用法
现在完成时:
the form of a verb that expresses an action done in a time period up to the present, formed in English with the present tense ofhave and the past participle of the verb, as inI have eaten
【语法】现在完成式(的);现在完成式的动词
a The present perfect simple is often used to talk about finished actions and events.
一般现在完成时经常用于谈论已经结束的行为和事件。
Another use of the present perfect is to talk about actions that have been repeated in a period up to the present.
现在完成时的另外一个用法是谈论行为其重复于某一时期直到现在。
Because their discovery took place in 1932 and is not ongoing, the correct verb tense is simple past, not present perfect.
因为他们的发现是在1932年举行，而不是持续的，正确的动词时态是一般过去，不是现在完成时。
The present perfect is also used for long actions and situations which started in the past and went on until very recently.
现在完成时也用于长久的行为和状态其始于过去而持续到最近。
We also use the present perfect to talk about a series of repeated actions which have happened up to the present.
我们也使用现在完成时谈论一系列重复的行为，这些行为到现在还发生。
When we talk about past events which have no present importance, we do not use the present perfect.
谈论过去的事件其对现在不重要，不用现在完成时。
This is a one-month learning English difficult to understand a tense, present perfect, but are also familiar with the points slowly.
这一个月的英语学习了一种较难理解的时态，现在完成时，不过慢慢的也熟悉了点。
The "present perfect progressive" is made with have been followed by an -ing form.
havebeen后面跟动词-ing形式，构成‘现在完成进行时’
We use the present perfect tense to talk about things that happened in the recent past , but are connected to the present.
我们用现在完成时听来谈论在不久的过去所发生的但是与选择相关的事情。
They were all concerning about the past tense and the present perfect.
那些练习题都是跟一般过去时和现在完成时有关的。