基礎 · Unit 51
to 不定詞 — 副詞用法
to 不定詞的副詞用法是附加在句子上，為句子補上目的、結果、情緒原因、判斷依據這類額外資訊的用法，其中又以目的(為了)最常用。
概念說明
to 不定詞的副詞用法是附加在句子上，為句子補上目的、結果、情緒原因、判斷依據這類額外資訊的用法，其中又以目的(為了~)最常用。
A. 目的 — 為了~
副詞用法中最常用的意思就是目的，表示「為了~、想要~」。要強調或講得正式一點時，可以換成 in order to / so as to。
| 形態 | 意思 | 例子 |
|---|---|---|
| to + 原形動詞 | 為了~ | I study to pass the exam. |
| in order to + 原形動詞 | 為了~ (強調) | I study in order to pass the exam. |
| so as to + 原形動詞 | 為了~ (正式) | Walk slowly so as not to slip. |
| 否定 in order not to | 為了不要~ | I ran in order not to be late. |
- She went to Paris to study French. (她為了學法文而去了巴黎。)
- I called him to invite him to my party. (我打電話給他，是為了邀他來我的派對。)
- We got up early in order to catch the first train. (我們為了趕上第一班火車而早起。)
- He whispered so as not to wake the baby. (他為了不吵醒寶寶而輕聲說話。)
B. 結果 — ~之後結果…
結果用法的意思是「~之後結果…」，常和 grow up、live、wake up 這類動詞一起用，加上 only to、never to 則可以強調出乎意料或負面的結果。
| 形態 | 意思 | 例子 |
|---|---|---|
| ~ to become | 長大後成為~ | He grew up to become a doctor. |
| ~ to find | ~之後發現… | She woke up to find it snowing. |
| ~ only to | ~了卻還是… | I ran, only to miss the bus. |
| ~ never to | 再也沒有~ | He left, never to return. |
- She grew up to become a famous writer. (她長大後成為有名的作家。)
- He lived to see his grandchildren. (他活到看見孫子的那一天。)
- I hurried to the station, only to find the train gone. (我趕到車站，結果火車已經開走了。)
- She woke up to find everyone gone. (她醒來才發現大家都走了。)
C. 情緒的原因與判斷的依據
接在 happy、glad、sad、sorry、surprised、lucky 這類情緒形容詞後面的 to 不定詞表示那個情緒的原因，接在 must be / can't be 後面時則表示「竟然~，一定是…」這種判斷的依據。
| 形態 | 意思 | 例子 |
|---|---|---|
| 情緒形容詞 + to 不定詞 | 因為~而… (原因) | I'm glad to hear that. |
| must be + 形容詞 + to | 竟然~，一定是… | She must be tired to sleep so long. |
| kind·clever·foolish of ~ + to | 竟然~，真是… | It's kind of you to help me. |
- We were surprised to see him at the party. (我們在派對上看到他而感到驚訝。)
- I'm sorry to hear the bad news. (聽到這個壞消息，我很遺憾。)
- She's lucky to have such good friends. (她能有這麼好的朋友真幸運。)
- He must be crazy to drive in this weather. (在這種天氣還開車，他一定是瘋了。)
重點整理
- 1副詞用法中最常用的意思是「為了~」的目的，要強調時可以換成 in order to / so as to。(例: I called him to invite him.)
- 2目的的否定形不是 not to，而是用 in order not to / so as not to 才自然，請記住這一點。(例: I ran in order not to be late.)
- 3grow up to、live to、wake up to 是帶有「長大後~、活到~、醒來發現~」這種結果意思的慣用組合。(例: He grew up to become a doctor.)
- 4接在 happy、glad、sad、sorry、surprised、lucky 這類情緒形容詞後面的 to 不定詞，表示那個情緒的原因。(例: I'm sorry to hear that.)
- 5must be / can't be + 形容詞 + to 不定詞表示「竟然~，一定是…、不可能是…」這種判斷的依據。(例: He must be tired to sleep so long.)
例句
I went to the store to buy some milk.
我為了買牛奶而去了商店。
She works hard to save money.
她為了存錢而努力工作。
I called him to invite him to the party.
我打電話給他，邀他來派對。
We got up early to catch the first train.
我們為了趕上第一班火車而早起。
He studied hard in order to pass the exam.
他為了通過考試而努力念書。
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
I went to the store to buy milk.
I ran so as not to be late.
He grew up to become a doctor.
I'm happy to see you.
She works hard to save money.
It's kind of you to help me.