介詞 + -ing

介詞（in、on、at、of、for、about、with、without、by、before、after、instead of…）後面接名詞。如果介詞後面直接跟動詞，這個動詞必須用 -ing 形式（動名詞）——不能用原形，也不能用 to + 動詞。

💡中文裡“之前”“通過”後面的動詞不變形（“出門之前”“通過坐公交”）。英語不一樣：緊跟在介詞後面的動詞必須加 -ing。只要看到 before、after、by、without、instead of、for、about… 後面跟著動詞，就檢查一下有沒有用 -ing。

1. By + -ing——做某事的方式，或得到結果的方法

• You can save a lot of money by cooking at home.

  在家做飯可以省下很多錢。

• She improved her English by watching films with English subtitles.

  她通過看帶英文字幕的電影提高了英語。

2. Without + -ing——本以為會發生的事沒有發生

• He left the party without saying goodbye.

  他沒說再見就離開了聚會。

• Don't go out without locking the door.

  出門別忘了鎖門。

3. Before / after + -ing——一個動作在另一個動作之前或之後

• Wash your hands before eating.

  飯前要洗手。

• After finishing university, Minh moved to Da Nang.

  大學畢業後，阿明搬到了峴港。

• Before leaving, please turn off the lights.

  離開前請關燈。（不說：Before to leave）

4. Instead of + -ing——做一件事來代替另一件事

• Instead of taking a taxi, we walked home.

  我們沒打車，而是走回了家。

• Why don't you call her instead of sending a message?

  你為什麼不給她打個電話，而是發訊息呢？

5. Thanks for / sorry for + -ing——為做過的事道謝或道歉

• Thanks for helping me with the move.

  謝謝你幫我搬家。

• Sorry for not replying sooner — I was busy with exams.

  抱歉沒早點回復——我忙著考試。（否定：not + -ing）

6. How about / what about + -ing——提出建議

• How about having a picnic this weekend?

  這個週末去野餐怎麼樣？

很多形容詞、動詞和名詞都有固定搭配的介詞（見“形容詞 + 介詞”和“動詞 + 介詞”兩課）。如果後面接的是動作，這個動詞也要用 -ing。

• My dad is really good at cooking Vietnamese food.

  我爸爸很會做越南菜。

• Phong is thinking about moving to Da Nang.

  阿峰在考慮搬到峴港。

• Did they succeed in finding a flat?

  他們找到房子了嗎？（不說：succeed to find）

• I love the idea of living in the countryside.

  我很喜歡住在鄉下這個想法。

可以在 -ing 前面加上一個人，表示誰做這個動作：I'm tired of people telling me what to do. We're worried about him driving at night.

通常 to 後面接動詞原形（want to go）。但在一些短語裡 to 是介詞，所以後面接名詞或 -ing：look forward to、be/get used to、object to、prefer … to …、when it comes to、in addition to。

• We're really looking forward to seeing you.

  我們非常期待見到你。（不說：to see）

• I prefer walking to driving in the city.

  在城裡我寧願走路也不願開車。

• When it comes to cooking, my brother is the expert.

  說到做飯，我哥哥可是行家。

💡檢驗方法：在 “to” 後面放一個名詞。如果句子仍然成立（I'm looking forward to the holiday），“to” 就是介詞 → 用 -ing。如果不成立（I want to the holiday——錯），就用動詞原形。另見“‘be used to’ + -ing”一課。

• 否定：把 not 放在 -ing 前面——Sorry for not calling. / She got sick by not eating properly.
• 被動：being + 過去分詞——He got into the building without being seen. / I hate the idea of being watched.
• 表示更早發生的動作，可以用 having + 過去分詞，但一般用普通的 -ing 就足夠清楚：He was proud of winning / of having won the prize.
• -ing 隱含的主語就是主句的主語：After finishing lunch, we went back to work（吃完午飯的是我們）。避免說 After finishing lunch, the meeting started——聽起來像是會議吃了午飯。
• before / after 也是連詞，所以也可以接完整的從句：Before I left, I called my mum. = Before leaving, I called my mum. 兩部分主語相同時，用 -ing 更簡潔。

• ✗I'm interested in learn Korean.

  ✓I'm interested in learning Korean.

  介詞 in 後面的動詞要用 -ing。

• ✗Before to leave, please turn off the lights.

  ✓Before leaving, please turn off the lights.

  before 是介詞，後面不接 to + 動詞。

• ✗Thanks for help me.

  ✓Thanks for helping me.

  for 是介詞 → helping。

• ✗He's thinking about to buy a car.

  ✓He's thinking about buying a car.

  介詞 + -ing，不接 to + 動詞。

• ✗She's good in drawing.

  ✓She's good at drawing.

  good 後面的介詞是 at。

• ✗He left without say anything.

  ✓He left without saying anything.

  without + -ing。