学习资料

[意       思]vt. 解开，打开
[例]  He undid the parcel. 他打开了包裹。
vt. 取消，消除
[例]  What's done cannot be undone. 覆水难收。

更多意思

vt.1.  打开，解开，拆开
2.  消除，取消，废止（某事的影响）
3.  打败，挫败

参考例句

1.	I can't undo my shoelaces.
	我解不开鞋带。
2.	The knot was fastened in such a way that it was impossible to undo .
	这个结系得那么紧,根本解不开。
3.	undo [untie] rope.
	解开绳子。
4.	We cannot undo the past.
	往事不能挽回。
5.	Please undo [untie] my apron strings for me.
	请替我把围裙带解开。