v.解开；松开；取消

Would you please undo this knot for me? 你能不能帮我把这个结解开？

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。

To return a database to its state as of the last committed change, i.e., to undo recent uncommitted changes. 使一个数据库返回到它上次已确认的改变之后的状态，即取消最近的尚未确认的变动。

A compensating transaction means that a new transaction will undo the effects of previous transactions. 补偿事务的意思是一个新事物会用于取消前一个事务的所有效果。

undo指将原本捆绑着的东西打开,如鞋带、包裹等,即“松开,解开”,主要强调解开的动作,而不强调解开的状态。引申可指“毁坏,败坏”。

undo多用作及物动词,后接名词或代词作宾语。可用于被动结构。

undo的过去式是undid,过去分词是undone。