题目

Traditionally, college students hold a graduation ceremony to encourage themselves before they on their life journey. A. give up      B. settle down C. get through  D. set off 答案：D。考查动词短语辨析。句意:传统上认为,大学生举行毕业典礼是为了在他们开始生活之旅之前为自己加油助威。set off动身,出发;give up放弃;settle down定居,平静下来,专心于;get through完成,接通(电话等)。 如图，在△ABC中，AB＝AC，DE垂直平分AB交AC于点E，已知△BCE的周长为8，且AC－BC＝2，求AB，BC的长．