---Shall I tell your best friends what happened to you yesterday?
— they ask you．
A. Not if
B. Not unless
C. Not except
D. Not though
网友回答
A. Not if
(答案→)B. Not unless
C. Not except
D. Not though
解析：考查连词。If 如果；unless 除非；except除了；though尽管。句意：我要告诉你最好的朋友你昨天发生了什么事吗？——不，除非他们问你。故选B。