The present perfect tense has a number of uses.
现在完成时态有许多使用方法。
1 We use it to talk about experience.
1 我们使用它讨论经验
• I’ve worked in 6 different countries.• Have you ever been to Australia?
• She’s won many awards for her books.
When these things happened is not important – the focus is on the action/state, not when it happened.
这些事情什么时候发生的并不重要，关键是现在的状态，而不是什么时候发生的。
If we say when we had the experience, we must use the past simple.
当我们说我们什么时候有的这个经验，我们必须使用一般过去时。
• I’ve visited Russia several times.• BUT I visited Russia for the first time in 1992.
We can never use the present perfect with a time in the past.
在有过去的时间时，我们不能用现在完成时。
• I have been to Spain in 2002.2 We also use the present perfect to talk about things that are unfinished – unfinished states and unfinished time periods.
我们也用现在完成时表述未完成的事情——未完成的状态和未结束的时间区间
• I’ve known him since I was 11. (unfinished state)I met him when I was 11. I still know him now. The present perfect is acting as a bridge between the past and the present.
当我11岁时，我见到他。我现在仍然知道他。现在完成时就像一个过去和现在的桥梁。
• I’ve had this watch for almost thirty years.• We’ve lived here since I was a boy.
• She’s been to the cinema three times this week. (unfinished time period)
This week isn’t finished yet – she may go to the cinema again.
本周还没有结束——她可能还会去电影院。
• We’ve already had two holidays this year.• I’ve eaten too much today.
3 A third use of the present perfect is to show the present result of a past action
3 现在完成时的第3个用法是展示过去行为的现在结果。
• I’ve lost my keys.He lost his keys some time in the past but the result – he can’t get into his house – is in the present.
他过去某段时间丢了钥匙，但结果是在现在——他不能进入房间。
• John’s broken his leg and he can’t go on holiday.• A storm has blown down the telephone lines. We’re stuck here!