I managed secretly to undo a corner of the parcel.

我设法偷偷地打开包裹的一角。

《柯林斯英汉双解大词典》

He tried to undo the knot by picking at it with his fingers.

他用手指不停地扯，想把绳结解开。

《牛津词典》

The knot was fastened in such a way that it was impossible to undo.

那个结系死了，没法解开。

《牛津词典》

In his speech on Thursday, President Obama challenged those lawmakers who are campaigning to undo his signature domestic issue.

VOA: standard.2010.03.25

The simile sets out to establish the moral polarities between good and evil, but it then works almost systematically to undo that understanding.

这里的比喻开始创造出善与恶之间的,两极性，然而后来它又几乎自动的抹去了这种理解。

耶鲁公开课 - 弥尔顿课程节选

As with the passage on the falling of the leaves there's a kind of elegiac tone that works to undo, or at least to challenge, our theological certainty.

在描写落叶的段落里,有一种挽歌式的腔调，似乎要抹掉，至少是挑战神学上的确定性。

耶鲁公开课 - 弥尔顿课程节选

New bureaucrats are hired to try to undo the damage caused by existing bureaucrats.

FORBES: We Don't Need TAG Accounts, We Need Sanity At The Fed

Our real economy is growing again, but too slowly to undo the damage of 2008-2009.

FORBES: Magazine Article

These trends make the recent attempts to undo healthcare reform all the more baffling.

FORBES: How Health Insurance Premiums Drag Down the Freelance Economy