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刷刷题刷刷变学霸
举一反三
【单选题】第二篇 Sleep We all know that the normal human daily cycle of activity is of some 7 - 8 hours’ sleep alternating with some 16 - 17 hours’ wakefulness and that, broadly speaking, the sleep n...
A.
people hate the inconvenience of working on night shifts.
B.
your life is disturbed by changing from day to night routines and back.
C.
not all industries work at the same hours.
D.
it is difficult to find a corps of good night workers.
【多选题】环境问题经历了哪几个阶段（）？A. 环境问题发展萌芽阶段 B.环境问题恶化阶段 C.第一次环境问题高潮阶段 D. 第二次环境问题高潮阶段
A.
A
B.
B
C.
C
D.
D