延续性动词和短暂性动词转换表：borrow变keep、buy变have、die变be dead，for/since/howl long必考
引言
现在完成时里有一对高频考点：延续性动词和短暂性动词。很多同学在 for/since 句型里用错动词直接丢分。一句话记住：时间段一出现，瞬间动词变状态。
核心概念：延续性动词 vs 短暂性动词
```text
短暂性动词（瞬间动词）：动作一下就做完，不能持续
buy（买）、borrow（借）、die（去世）、leave（离开）
arrive（到达）、begin（开始）、join（加入）
延续性动词：动作可以持续一段时间
能和 for、since、how long 连用
```
高频转换表
```text
瞬间动词 → 延续状态
borrow 借 → keep 借了（一段时间）
buy 买 → have 拥有
die 去世 → be dead 已去世（状态）
leave 离开 → be away 已离开（状态）
join 加入 → be in 在其中
begin 开始 → be on 进行中（状态）
```
考点一：for / since / how long 出现，短暂动词必须换
```text
for + 时间段（for three days）
since + 时间点（since 2020）
how long 提问（持续多久）
He has bought the book for three days. ✗ 错误
He has kept the book for three days. ✓ 正确
```
考点二：一般过去时不受限制
```text
一般过去时可以直接用瞬间动词 + 过去时间
I bought the book two years ago. ✓ 正确（ago 表过去时间点）
（改成现在完成时：I have had the book for two years.）
```
考点三：have been to / have gone to / have been in
```text
have gone to 去了（未回来）
have been to 去过（已回来）
have been in 待在某地（延续性结构）
Tom isn't here. He has gone to the library.
我去过北京两次。I have been to Beijing twice.
他住上海三年了。He has been in Shanghai for three years.
```
考点四：句型转换必考
```text
原句：He left an hour ago.（他一个小时前离开的）
改句：He has been away for an hour.（已经离开一小时了）
关键：leave → be away，ago 时间段 → for an hour
```
考点五：否定句可以直接搭配 for / since
```text
短暂动词的否定句可以接 for/since
因为"没有做动作"本身就是一种可持续状态
I haven't left home for three days. ✓ 正确（不用改成 be away）
He hasn't bought anything since Monday. ✓ 正确
```
实战练习
```text
- The movie has ______ for ten minutes.（begin 换成延续状态）
→ been on
- He ______ the car for two years.（buy 换成延续状态）
→ has had
- She ______ in the army for three years.（join 换成延续状态）
→ has been
- I bought this phone two years ago.（改成现在完成时）
→ I have had this phone for two years.
```
总结
```text
短暂动词动作一下就完，延续动词可以持续
for + 时间段、since + 时间点、how long 提问
→ 瞬间动词必须换成延续状态
一般过去时不受限，可直接用瞬间动词
否定句例外：短暂动词否定可以直接接 for/since
口诀：时间段一出现，瞬间动词变状态
```
```text
今日小抄：
borrow→keep buy→have die→be dead
leave→be away join→be in begin→be on
He has been away for an hour.
I haven't left home for three days.
```