基礎 · Unit 48
to 不定詞 — 名詞用法
to 不定詞的名詞用法，是讓「to + 原形動詞」當成意思為「這件事」的名詞片語，放進主詞、受詞、補語的位置來使用。
概念說明
to 不定詞的名詞用法，是讓「to + 原形動詞」當成意思為「~這件事」的名詞片語，放進主詞、受詞、補語的位置來使用。
A. 主詞位置 — ~這件事
to 不定詞放在句首時，就扮演「~這件事」這個主詞的角色，這時動詞一律當單數看待。公式是 to + 原形動詞 = ~這件事。
| 形式 | 位置 | 例子 |
|---|---|---|
| To + 原形動詞 | 句首 (主詞) | To read books is my hobby. |
| To + 原形動詞 | 句首 (主詞) | To speak English well takes time. |
| To + 原形動詞 | 句首 (主詞) | To learn a new language is exciting. |
- To exercise every day is healthy. (每天運動對健康有益。)
- To wake up early is difficult for me. (早起對我來說很困難。)
- To travel abroad is her lifelong dream. (出國旅行是她一生的夢想。)
B. ^^ 受詞位置 — 做這件事 / 要做 ^^
to 不定詞放在特定動詞後面時，扮演「做這件事、要做」這個受詞的角色，和 want·decide·hope·plan·promise·expect 這類表示未來、願望的動詞很搭。
| 動詞 | 意思 | 例子 |
|---|---|---|
| want to | 想要~ | I want to travel more. |
| decide to | 決定要~ | We decided to leave early. |
| hope to | 希望能~ | She hopes to see you again. |
| plan to | 計畫要~ | They plan to open a cafe. |
| promise to | 答應要~ | He promised to help me. |
| expect to | 預期會~ | I expect to finish by 6. |
- I want to buy a new laptop. (我想買一台新的筆記型電腦。)
- She decided to study abroad. (她決定出國留學。)
- We hope to meet you next year. (我們希望明年能見到你。)
- He promised to call me tonight. (他答應今晚打電話給我。)
C. 補語位置與 It 虛主詞句型
to 不定詞放在 be 動詞後面的補語位置時，意思是「就是做~這件事」，而當主詞因為 to 不定詞片語而變長時，在句首放 It、把真正的主詞移到後面的 It 虛主詞句型自然得多。
| 類型 | 形式 | 例子 |
|---|---|---|
| 補語 | be 動詞 + to 不定詞 | My goal is to save money. |
| It 虛主詞 | It is 形容詞 + to 不定詞 | It is easy to make a mistake. |
| It 虛主詞 | It is 名詞 + to 不定詞 | It is a joy to see you. |
- Her plan is to open her own shop. (她的計畫是開一家自己的店。)
- It is important to eat breakfast. (吃早餐很重要。)
- It is fun to learn new things. (學習新事物很有趣。)
- It is hard to wake up in winter. (冬天要起床很難。)
重點整理
- 1to 不定詞的名詞用法意思是「~這件事」，主詞、受詞、補語三個位置都能用，請先抓住這個大方向。(例: I want to go.)
- 2want·decide·hope·plan·promise·expect 這類表示未來、願望的動詞會用 to 不定詞當受詞，請把這一組背起來。(例: We decided to leave.)
- 3to 不定詞當主詞時動詞一律用單數，會話中 It 虛主詞句型自然得多，請培養這個語感。(例: It is important to eat breakfast.)
- 4to 不定詞後面一定接原形動詞，不會因為主詞或時態而改變形式，請記住這個規則。(例: to go (O) / to went (X))
- 5中文裡動詞片語不用加任何標記就能放進名詞的位置，這種情況在英語中大多可以用 to 不定詞來表達。
例句
To learn English is fun.
學英文很有趣。
To exercise every day is healthy.
每天運動對健康有益。
To travel around the world is my dream.
環遊世界是我的夢想。
I want to visit Paris someday.
我想有一天去巴黎。
She decided to change her job.
她決定換工作。
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
To learn English is fun.
I want to go home.
She decided to study abroad.
It is important to eat breakfast.
He promised to call me.
To wake up early is difficult.