backup——作为形容词，backup的意思是后备，替代。



媒体报道说，布什总统实施新的伊拉克计划之后，一些州长在白宫询问布什和参谋长联席会议主席Peter Pace有没有后备计划，

"A group of governors asked President Bush and chairman of the Joint Chief of Stuff Peter Pace about their backup plan for Iraq."

州长们后来说，他们认为白宫并没有后备计划。许多人认为伊拉克计划很可能失败，政府必须要有后备的战略，

"The United States must have backup strategy for Iraq."