特殊字符”<”字符代码是（）
A. <
B. >
C. &
D. ®
The main theme of the passage is _______.
A. the effects of lack of sleep
B. sleep and body temperature
C. how easily people can get used to working at night
D. the effect of automation on working efficiency
Why is the question no mere academic one (Para.2)?
A. Because of research by Bonjer and Brown.
Because sleep normally coincides with the hours of darkness.
C. Because some people can change their sleeping habits easily.
D. Because shift work in industry requires people to change their sleeping habits.
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