现在完成时
Present Perfect
现在完成时把过去和现在联系起来。用于经历、与现在相关的近期事件，或者从过去开始延续到现在的动作。由 have/has + 过去分词 构成。
何时使用
用于人生经历（没有具体时间）、对现在有影响的近期动作、从过去延续至今的动作（与 "for" 或 "since" 搭配），以及引入新闻标题。
结构
S + have/has + past participleShe has visited Japan three times.
她**去过**三次日本。
S + haven't/hasn't + past participleI haven't seen that film yet.
我**还没看过**那部电影。
Have/Has + S + past participle?Have you ever tried sushi?
你**尝过**寿司吗？
信号词
- ever
- never
- already
- yet
- just
- for
- since
- recently
- lately
- so far
例句
I have visited Japan three times.
我**去过**三次日本。
She has just finished her homework.
她**刚刚做完**作业。
Have you ever tried sushi?
你**尝过**寿司吗？
They haven't arrived yet.
他们**还没到**。
He has lived here for ten years.
他在这里**住了**十年了。
拼写规则（第三人称单数）
| 规则动词 | 加 -ed（与一般过去时相同） | work → worked, play → played |
|---|---|---|
| 不规则动词 | 独特的过去分词形式 | go → gone, eat → eaten, write → written |
常见错误
I have seen her yesterday.
I saw her yesterday.
不要把 present perfect 与具体的过去时间搭配。改用 past simple。
Have you eaten yet? — Yes, I have eaten.
Have you eaten yet? — Yes, I have.
简短回答中不要重复过去分词 —— 只用 "have/has" 即可
提示
present perfect 与 past simple 的关键区别：present perfect = 具体时间不知道或不重要。Past simple = 提到或暗示了具体时间（yesterday, last week...）。