1.【2018·江苏】29. _______ you can sleep well, you will lose the ability to focus, plan and stay motivated after one or two nights.
A. Once B. Unless
C. If D. When
【答案】B
【解析】考查连词词义辨析及语境理解。句意:除非你睡得好,否则一两个晚上之后,你会失去专注、计划和保持动力的能力。A. Once一旦;B. Unless除非;C. If如果;D. When当……时候。故选B。
点睛:本题考查连词辨析。解题时要区分清选择项的含义与区别,再联系句意进行判断,从而选出正确答案。