.I won’t call you, something unexpected happens.
A. unless
B. whether
C. because
D. while
网友回答
(答案→)A. unless
B. whether
C. because
D. while
解析:unless的意思是“除非”,又如:Don’t call me unless you need help. 除非你需要帮助否则别打电话找我。Unless you change your mind, I won’t be able to help you. 除非你改变你的想法,否则我不能帮助你。