n.拆除；取消

It's important to backout Beijing's wall in the capital's history. 拆除城墻是首都發(fā)展史上的重大事件。

In the total process of the construction project, the risk has an important influence on the life-cycle cost from the decision-making and the running phase to the backout phase. 摘要在建設項目從決策設計到實施運行直到拆除的全過程中，風險對全生命周期的造價影響貫穿其中。