把繫住的解開（手上的）
這一族最貼近核心畫面：用手把某個已經扣好、綁好的東西反向鬆開，是這個字最看得見、最好想像的樣子。
untie, unfasten · verb · B1
To open something that is tied, fastened, or wrapped, such as buttons, a zip, a knot, a ribbon, a screw, or a seat belt.
解開；鬆開
核心畫面
Something was done — a knot tied, a button — and you run the doing backwards until it is as if it had never been done. Not breaking it, not cutting it: reversing the exact steps, so the thing returns to its earlier state.
有件事已經「做好了」——繩子打了結、扣子扣上了——而你把那個動作倒著走一遍，讓它回到還沒做之前的樣子。重點在「倒著走…更多收起
有件事已經「做好了」——繩子打了結、扣子扣上了——而你把那個動作倒著走一遍，讓它回到還沒做之前的樣子。重點在「倒著走」：不是剪斷、不是弄壞，是把當初的步驟反過來執行，所以東西完好地回到原狀。do 是做，un- 是反過來，undo 就是「把做過的做回去」。英文裡這個 un- 加在動詞前面常常是這個意思（unlock、unpack、unwrap），一個學到就能認一整組的線索。Three branches
把造成的後果收回
把「倒著走一遍」從手上的東西搬到已經發生的事情上：同樣是想回到之前的狀態，只是這次要解開的不是結，而是後果。
reverse, repair damage · verb · B2
To try to remove or repair the bad effects of something that has already been done or has already happened.
挽回；彌補
電腦上的復原
這一族是核心畫面被機器實現出來：電腦記得你剛才做了什麼，所以真的能替你把那一步倒著走回去。
undo (computer) · verb · B1
To remove the effect of the last thing you did on a computer or phone, so that your work goes back to the way it was before.
復原；還原上一步
原始詞典資料6 筆記錄
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
undoverb詞源 1/ʌnˈduː/
- 1
To reverse the effects of an action.
- Fortunately, we can undo most of the damage to the system by the war.
- What's done can't be undone.
- 2
To unfasten.
- Could you undo my buckle for me?
- 3
To unfasten the clothing of (a person).
- PROSTITUTE: Undo me. There's a dear.
- 4
To impoverish or ruin, as in reputation; to cause the downfall of.
- Woe is me, for I am undone!
undonoun詞源 1/ʌnˈduː/
- 1
computingengineeringmathematicsAn operation that reverses a previous action.
- How many undos does this program support?
這個拼法也被記錄為下列字的變化形：
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。