(41). We all know that normal human daily cycle of activity is of some 7-8 hours’ sleep alternating with some 16-17 hours’ wakeful ness and that, broadly speaking, the sleep normally coincides with the hours of darkness.
Our present concern is with how easily and to what extent this normality can be modified.
(42). The question is no more an academic one. The case, for example, with which people can change from working in the day to working at night is a question of growing importance in industry where automation calls insistently for round - the - clock working. of machine. It normally takes from five days to one week for a person to adapt to a reversed routine of sleep and wakefulness sleeping during the day and working at night. Unfortunately, it is often the case in industry that shifts are changed every week, a person may work from 12 midnight to 8 a.m. one week, 8 a.m. to 4 p.m. the next, and 4 p. m. to 12 midnight the third and so on. This means
| We all know that the normal human daily
cycle of activity is of some 748 hours’ sleep alternating with some 16417 hours’
wakefulness and that, broadly speaking, the sleep normally coincides with the
hours of darkness. Our present concern is with how easily and to what extent
this cycle can be modified. The question is no mere academic one. The ease, for example, with which people can change from working in the day to working at night is a question of growing importance in industry where automation calls for round the-clock working of machines. It normally takes from five days to one week for a person to adapt to a reversed routine of sleep and wakefulness, sleeping during the day and working at night. Unfortunately, it is often the case in industry that shifts are changed every week: a person may work from 12 midnight to 8 a.m. one week, 8 a.m. to 4 p.m. A. Because few people like to reverse the cycle of sleep and wakefulness. B. Because sleep normally coincides with the hours of darkness. C. Because people are required to work at night in some fields of industry. D. Because shift work in industry requires people to change their sleeping habits. [单项选择]We all know that the normal human daily cycle of activity is of some 748 hours’ sleep alternating with some 16,417 hours’ wakefulness and that, broadly speaking, the sleep normally coincides with the hours of darkness. Our present concern is with how easily and to what extent this cycle can be modified.
The question is no mere academic one. The ease, for example, with which people can change from working in the day to working at night is a question of growing importance in industry where automation calls for round the-clock working of machines. It normally takes from five days to one week for a person to adapt to a reversed routine of sleep and wakeful-ness, sleeping during the day and working at night. Unfortunately, it is often the case in industry that shifts are changed every week: a person may work from 12 midnight to 8 a. m. one week, 8 a. m. to 4 p. m. the next, and 4 p. m. to 12 midnight the third and so on. This means that no sooner has he got used to one routine than he A. Because few people like to reverse the cycle of sleep and wakefulness. B. Because sleep normally coincides with the hours of darkness. C. Because people are required to work at night in some fields of industry. D. Because shift work in industry requires people to change their sleeping habits. 我来回答: 提交
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