進階 · Unit 9
to 不定詞 — 時態
to 不定詞的形態本身就帶有時態資訊，單純不定詞表示與主要子句相同的時間點，完成式不定詞則表示比主要子句更早的時間點。決定時態時，要先判斷主要子句動詞和 to 不定詞動作之間的時間關係。
概念說明
to 不定詞的形態本身就帶有時態資訊，單純不定詞表示與主要子句相同的時間點，完成式不定詞則表示比主要子句更早的時間點。決定時態時，要先判斷主要子句動詞和 to 不定詞動作之間的時間關係。
A. 單純不定詞 — 與主要子句相同的時間點
單純不定詞 to + 原形動詞表示與主要子句動詞相同的時間點，或是往後的時間點。主要子句是現在式時 to 不定詞也是現在，主要子句是過去式時 to 不定詞指的也是那個過去時間點的事。
| 主要子句時態 | to 不定詞的時間點 | 例句 |
|---|---|---|
| 現在 | 現在 | He seems to be sick. |
| 過去 | 那個過去的時間點 | He seemed to be sick. |
| 指向未來 | 往後 | I hope to see you soon. |
- She appears to know the answer. (她好像知道答案。)
- I'm sorry to bother you. (不好意思打擾你。)
- We hope to travel next year. (我們希望明年去旅行。)
B. 完成式不定詞 — 比主要子句更早的時間點
完成式不定詞 to have + 過去分詞表示比主要子句動詞更早發生的事。請把to have + 過去分詞 = 比主要子句更早 這個時間關係像圖像一樣記起來。主要用在 seem、appear、be said、be thought 後面，或是情緒形容詞後面。
| 主要子句時態 | to have + p.p. 的意思 | 例句 |
|---|---|---|
| 現在 seems | 好像之前是那樣 | He seems to have left. |
| 過去 seemed | 好像在那之前就是那樣了 | He seemed to have left. |
| 情緒形容詞 | 對之前的事的感受 | I'm glad to have met you. |
- She seems to have forgotten our appointment. (她好像忘了我們的約定。)
- He is said to have studied in Paris. (據說他在巴黎唸過書。)
- I'm sorry to have kept you waiting. (讓你久等了，不好意思。)
- They appear to have finished the work. (他們好像已經完成工作了。)
C. 兩種時態的比較 — 相同句子，不同時間點
即使主要子句相同，只要把 to be 換成 to have been，to 不定詞所指的時間點就會不一樣。像下面這樣成對對照來看，就能抓到時態的語感。
| 單純不定詞 (相同時間點) | 完成式不定詞 (更早的時間點) |
|---|---|
| He seems to be tired. | He seems to have been tired. |
| She is happy to see him. | She is happy to have seen him. |
| I'm sorry to hear that. | I'm sorry to have heard that. |
- He seems to know the truth. (他好像知道真相。)
- He seems to have known the truth. (他好像早就知道真相了。)
- She is glad to meet him. (她很高興見到他。)
- She is glad to have met him. (她很高興曾經見過他。)
重點整理
- 1單純不定詞(to + 原形動詞)表示與主要子句動詞相同的時間點，完成式不定詞(to have + 過去分詞)表示比主要子句更早的時間點，這個時間關係就是核心。(例: He seems to be / He seems to have been.)
- 2seem、appear、be said、be thought 後面接完成式不定詞時，就是委婉傳達比主要子句時間點更早的事，把這個句型學起來。(例: He seems to have left.)
- 3情緒、評價形容詞(happy、sorry、glad、proud)後面也可以用完成式不定詞，來表達對已經發生的事的感受，記住這個用法。(例: I'm sorry to have kept you waiting.)
- 4中文的「好像~」和「好像已經~了」分別對應單純不定詞和完成式不定詞，掌握這個語感之後，時態的選擇就會變得容易。
- 5完成式不定詞本身就是把時間往前移的裝置，所以即使主要子句是現在式，to have + p.p. 指的仍然是過去的事，這一點和時態一致的概念不同。
例句
He seems to be busy these days.
他最近好像很忙。
She appears to know the answer.
她好像知道答案。
I hope to see you again soon.
我希望很快能再見到你。
We are happy to help you.
我們很樂意幫你。
I'm sorry to bother you at this hour.
這個時間打擾你，很不好意思。
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
He seems to have been tired.
She seems to have left.
I'm sorry to have kept you waiting.
He is said to have lived in London.
They appear to have finished the work.