定义 / 说明
past simple 描述发生在已结束过去时间里的完成动作。present perfect 描述与现在有联系的过去动作，或不强调具体结束时间的动作。两者都指过去，但回答的问题不同：past simple 回答 When did it happen?；present perfect 回答“它是否在你的人生/本周/到现在为止发生过”。
关键规则
- 与已结束时间状语连用时用 past simple：yesterday, last week, in 2019。
- 当不说具体时间或强调现在结果时用 present perfect。
- 对比：I saw him yesterday vs I have seen him this week。
- 叙事时间线通常用 past simple。
- 近期新闻、经历、未结束时间段常用 present perfect。
例句
- I saw him yesterday, but I have seen him twice this week. - 我昨天见过他，但这周我已经见过他两次了。
- She left at six, so I have not spoken to her today. - 她六点就走了，所以我今天还没和她说上话。
- We went there last month, and we have been there many times before. - 我们上个月去了那里，而且之前也去过很多次。
- He broke his phone last night, so he has bought a new one. - 他昨晚摔坏了手机，所以他买了新的。
- They did not finish the job yesterday, but they have finished it now. - 他们昨天没完成这项工作，但现在已经完成了。
常见错误
- ❌ I have seen him yesterday. -> ✅ I saw him yesterday.
- ❌ She went to the gym this week. -> ✅ She has gone to the gym this week.
- ❌ We have did it already. -> ✅ We have done it already.