以下内容以 Cambridge Dictionary 为中心来编辑。
Present perfect tense
1. The form of the verb used for actions or events that have been completed or have happened in a period of time up to now:
在一段时间内完成的动作或事件的动词形式:
- The sentences "She has talked to her doctor about the problem(已经说了)" and "I have never been to Australia(没有去过，到现今)" are all in the present perfect.
- 'I have seen it' is an example of the present perfect.
- The sentence 'I have told him' is in the present perfect tense.
以上两句，你试着自己理解看看。
2. The tense you use to talk about actions or events that happen in both the past and the present:
用来谈论过去和现在发生的动作或事件的时态:
The sentence "She has broken her leg (发生到现在)" is in the present perfect.
Present perfect tense 大多数用于发生到现在或者现在发生的事。（注:我自己的理解。）
辅助资料:
https://dictionary.cambridge.org/zhs/%E8%AF%8D%E5%85%B8/%E8%8B%B1%E8%AF%AD/present-perfect
Past perfect tense
1. the grammatical form used for an action that had already finished when another action happened. It is made with "had" and a past participle:
当另一个动作发生时，一个动作已经结束了。它由had和过去分词组成:
- "I had just cooked (已经发生了，并且完成了)" is an example of the past perfect, and "I had just been cooking (已经发生了，并且在过去时持续发生，也是已经完成了)" is an example of the past perfect continuous.
“I had just cooking”是过去完成时的例子，而“I had just been cooking”是过去完成进行时的例子。
- 'I had already eaten' is an example of the past perfect.
- 'She hadn't seen him' is an example of the past perfect
这两句你也试着理解。
- A tense usually formed with "had" that is used to refer to the earlier of two different times in the past:
2. 一种时态，通常由“had”构成，用来指过去两个不同时期的较早的:
- The sentence "She had broken her leg once before (已经发生了)" is in the past perfect.
其实这第一个解释与第二个解释都是差不多一样的，但是一个是用英式辞典，另一个是美式辞典。
辅助资料:
https://dictionary.cambridge.org/zhs/%E8%AF%8D%E5%85%B8/%E8%8B%B1%E8%AF%AD/past-perfect
应该就是这样了！希望你能明白。
如果我说错了什么，请在下方评论，我会修改，谢谢合作。
不喜勿喷，若冒犯到你，深感抱歉。
