A.Travel otherwise.B.Modify his reservation.C.Cancel his travel plans.D.Await a plane tick

学历类 专四 已帮助 人

A.Travel otherwise.

B.Modify his reservation.

C.Cancel his travel plans.

D.Await a plane ticket.

请帮忙给出正确答案和分析,谢谢!

热搜:a是b的充分条件,b是a的必要条件吗