| have studied for 3 years | B1 现在完成 | 从3年前持续到现在 → 对当前时间点有影响 |
| had studied for 3 years | B1 过去完成 | 从更早前持续到过去的某时 → 对那个过去时间点有影响 |
| stayed for 3 months last year | A1 一般过去 | 去年持续了3个月,已结束,不强调对任何时间点的影响 |
| Step | 操作 |
|---|---|
| 1 | 找出句中所有谓语动词 |
| 2 | 判断每个动词的关联时间 |
| 3 | 判断每个动词采用的状态(A/B) |
| 4 | 确定时态,套用对应写法 |
| gets up early | 一般现在 | 时间现在 —— 习惯性或经常发生 · often / usually / twice a week |
| used to get up early | 一般过去 | 时间过去 —— 习惯性或经常发生 · used to do / often / usually |
| by + 时间点 | 完成 | 强调对这个时间点的影响 —— She had finished the work by 1999. |
| by + 时间点 | 一般 | 强调在这个时间前发生 —— I will lend you the money by next month. |
| for + 时间段 | 完成 | 强调对现在的影响 —— I have studied English for 3 months. |
| for + 时间段 | 一般 | 强调行为发生在去年 —— I stayed in China for 3 months last year. |