—Why not talk with your parents about your willingness to attend Peking University Summer Camp?
—I tried to get them to listen to me.
A. in time
B. in vain
C. in need
D. in case
网友回答
A. in time
(答案→)B. in vain
C. in need
D. in case
解析： 本题考查介词短语。句意：--为什么不告诉你的父母关于你想参加北京大学夏令营的事？----我试着说服让他们听我的，但没用。in vain白费地；徒劳无益地；无效果的；无用的。