動詞 undo:

1. cancel, annul, or reverse an action or its effect
   同義詞：undo
2. deprive of certain characteristics
   同義詞：unmake, undo
3. cause the ruin or downfall of
   同義詞：undo
4. cause to become loose
   同義詞：untie, undo, loosen
5. remove the outer cover or wrapping of
   同義詞：unwrap, undo

形容詞 undone:

1. not done
2. doomed to extinction
   同義詞：done for, ruined, sunk, washed-up
3. not fastened or tied or secured
4. thrown into a state of disorganization or incoherence
   同義詞：unstuck

1. What is done cannot be undone.
   已做的事是既成事實。
2. What's done cannot be undone.
   覆水難收。
3. That mistake has undone all our good work.
   那個過錯使我們前功盡棄。
4. Our folly has undone us.
   我們的愚蠢行為將自己毀了。
5. He was gone and left all the work undone to me.
   他走了，把所有沒做完的工作都留給了我。
6. One of your buttons is undone.
   你的一個扣子松開了。