现在完成时是初中语法的分水岭，中考单选和完形年年考。丢分三大源：since 和 for 混用、have been to 与 have gone to 分不清、短暂动词误接一段时间。一篇全解决。
结构与标志词
| 项目 | 内容 | 例句 |
|---|---|---|
| 结构 | have / has + 过去分词 | I have finished my homework. |
| 标志词一 | already（已经）、yet（还）、just（刚刚） | He has already left. Has it stopped yet? |
| 标志词二 | ever、never（曾经、从未） | Have you ever been to Beijing? |
| 标志词三 | since + 时间点，for + 时间段 | I have lived here since 2020 / for five years. |
| 否定与疑问 | haven't / hasn't；Have you ... ? | She hasn't seen the film yet. |
常用动词的过去分词
- 规则动词与过去式相同：work - worked - worked
- AAA 型：read - read - read、cut - cut - cut
- ABA 型：come - came - come、become - became - become
- ABB 型：buy - bought - bought、see - saw - seen、write - wrote - written
- ABC 型：do - did - done、go - went - gone、eat - ate - eaten、be - was/were - been
核心含义：动作发生在过去，但对现在有影响或一直持续到现在。中文里「已经做过」「去过」「学了多久」多数用现在完成时。
辨析：have been to vs have gone to
have been to 表示去过且已回来——He has been to Beijing twice（人在这儿，有去过两次的经历）；have gone to 表示去了还没回——He has gone to Beijing（人不在，说话时对方也找不到他）。判断方法：主语是第三人称且人不在场选 has gone to；描述经历、去过几次选 have been to。另一个必考点：短暂动词 borrow、buy、die、join 不能和 for 引导的时间段连用，要说 I have kept this book for two weeks（borrow 换 keep）、He has been dead for a year（die 换 be dead）。