1. He has undone the good work of his predecessor.
    他已毁了他前任取得的良好成就。

2. What''s done cannot be undone.
    覆水难收。

3. Please undo the package.
    请解开这包裹。

4. He undid the parcel.
    他打开了包裹。

5. In 5 minutes he undid my whole day''s work.
    他五分钟就把我花一整天做成的事给毁坏了。

1. 还原：易学易用 - 还原(undo)及改善的面板编辑功能,提高了程式的开发速度. 观看

1. 解开；松开；打开
    If you undo something that is closed, tied, or held together, or if you undo the thing holding it, you loosen or remove the thing holding it.

    e.g. I managed secretly to undo a corner of the parcel...
           我悄悄地设法解开了包裹的一角。
    e.g. I undid the bottom two buttons of my yellow and grey shirt...
           我解开了自己黄灰相间的衬衫上最下面的两个纽扣。

2. 撤销；抵消；消除
    To undo something that has been done means to reverse its effect.

undo的反义词

    e.g. A heavy-handed approach from the police could undo that good impression...
           警方采取高压手段可能会毁掉之前留下的好印象。
    e.g. She knew it would be difficult to undo the damage that had been done...
           她知道想要消除已经造成的损害是很难的。

3. 破坏；毁掉
    If a person, organization, or plan is undone by something, that thing causes their failure.

    e.g. They were undone by a goal from John Barnes...
           约翰·巴恩斯的一粒进球使他们落败。
    e.g. Macbeth is the story of a Scottish soldier who becomes king but is undone by his own ambition.
           《麦克白》讲述的是一个苏格兰士兵当上了国王，却毁于自己的野心。

4. see also: undoing;undone

1. remove the outer cover or wrapping of

    e.g. Let''s unwrap the gifts!
           undo the parcel

    Synonym: unwrap

2. cause to become loose

    e.g. undo the shoelace
           untie the knot
           loosen the necktie

    Synonym: untieloosen

3. cancel, annul, or reverse an action or its effect

    e.g. I wish I could undo my actions

4. deprive of certain characteristics

    Synonym: unmake

5. cause the ruin or downfall of

    e.g. A single mistake undid the President and he had to resign