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」：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。
登入就可以看每一支怎麼連回核心畫面。
原始詞典資料6 筆記錄
以下是外部詞典記錄的用法，摘錄並精簡格式，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：
摘錄自 英文維基詞典 English Wiktionary，已精簡格式；依 CC BY-SA 4.0 授權使用，改動後的內容同樣以此授權提供。