進階 · Unit 82
助動詞 — 過去的推測 (must / may / might / could + have p.p.)
對過去事情的推測·猜想用「助動詞 + have + 過去分詞」的形態來表達，確信的程度會隨助動詞的種類而不同。助動詞 + have + 過去分詞 = 過去的推測。
概念說明
對過去事情的推測·猜想用「助動詞 + have + 過去分詞」的形態來表達，確信的程度會隨助動詞的種類而不同。助動詞 + have + 過去分詞 = 過去的推測。
A. must have p.p. — 強烈確信的推測 (一定是~了)
根據現在的證據強烈推測過去的事情時，用 must have + 過去分詞。用在說話者有 90% 以上把握的時候，而相反方向的強烈確信「不可能~」不是用 mustn't have，而是用 can't have。
| 情況 | 句子 | 說話者的推論 |
|---|---|---|
| 窗戶是濕的 | It must have rained. | 確定下過雨 |
| 他在笑 | He must have heard good news. | 應該是聽到了好消息 |
| 她沒有來 | She must have been sick. | 一定是生病了 |
- The ground is wet. It must have rained last night. (地上是濕的。昨天晚上一定下過雨。)
- He didn't answer. He must have been busy. (他沒有回答。他一定是很忙。)
- She looks tired. She must have worked all night. (她看起來很累。她一定是整晚都在工作。)
- They must have finished the meeting by now. (他們現在應該已經開完會了。)
B. may / might / could have p.p. — 微弱的推測·可能性 (也許~了)
may / might / could + have + 過去分詞表示「也許了 / 有可能了」這種微弱的推測·可能性。三者的意思幾乎相同，只是 might 給人的感覺更不確定一些。
| 助動詞 | 確信程度 | 例句 | 意思 |
|---|---|---|---|
| may have p.p. | 微弱的推測 | She may have called while I was out. | 也許打過電話 |
| might have p.p. | 更不確定 | He might have forgotten. | 也許忘了 (更弱) |
| could have p.p. | 可能性 | They could have taken the wrong train. | 有可能搭錯了火車 |
- She's not answering. She may have gone out. (她沒有接電話。她可能出去了。)
- The keys are gone. Someone might have taken them. (鑰匙不見了。可能有人拿走了。)
- He's late. He could have missed his flight. (他遲到了。他有可能錯過班機了。)
- I don't know where she is. She might have left early. (我不知道她在哪裡。她可能提早離開了。)
C. can't / couldn't have p.p. — 強烈的否定推測 (不可能~)
強烈否定過去的事情、認為絕對不可能時，用 can't have + 過去分詞或 couldn't have + 過去分詞。這時候不會用 mustn't have p.p.，這一點常讓人搞混。
| 情況 | 句子 | 說話者的推論 |
|---|---|---|
| 她當時在別的地方 | She can't have stolen it. | 不可能是她偷的 |
| 昨天才說過 | He can't have forgotten already. | 不可能這麼快就忘了 |
| 30 分鐘前才看到 | They couldn't have left yet. | 不可能已經離開了 |
- He was with me all day. He can't have taken your bag. (他一整天都跟我在一起。他不可能拿走你的包包。)
- She can't have been there. I saw her at the office. (她不可能在那裡。我在辦公室看到她。)
- You couldn't have finished already. It was 40 pages. (你不可能已經看完了。那有 40 頁。)
- He can't have said that. He's too polite. (他不可能說那種話。他非常有禮貌。)
重點整理
- 1過去的推測用助動詞 + have + 過去分詞，確信的程度會隨助動詞而不同。(例: must have / may have / might have / could have / can't have)
- 2must have p.p. 是「一定~了」的強烈確信，can't have p.p. 是「不可能~」的強烈否定確信，兩者是相反的一對。不會用 mustn't have。
- 3may have 和 might have 意思幾乎相同，只是 might 的語感更不確定一些。
- 4could have p.p. 除了可能性的推測，還有「本來可以~(結果沒做)」這種後悔·遺憾的意思，要靠上下文區分。
- 5have 是助動詞，不管主詞是誰都維持 have，後面一定要接過去分詞。(X: She must has gone / O: She must have gone)
例句
He must have missed the bus.
他一定是錯過公車了。
The ground is wet. It must have rained last night.
地上是濕的。昨天晚上一定下過雨。
She looks tired. She must have worked all night.
她看起來很累。她一定是整晚都在工作。
They must have finished the meeting by now.
他們現在應該已經開完會了。
She may have forgotten our meeting.
她可能忘了我們的約。
這個單元還有更多例句。註冊後可以看完整內容並聆聽發音。
容易犯的錯誤
She must have forgotten.
He can't have taken it.
They might have gone home.
He must have missed the bus.
She can't have been there.