未知题型 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 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 that no sooner has he got used to one routine than he has to change to another, so that much of his time is spent neither working nor sleeping very efficiently.The only real solution appears to be to hand over the night shift to a number of permanent night workers. An interesting study of the domestic life and health of night shift workers was carried out by Brown in 1957. She found a high incidence of disturbed sleep find other disorders among those on alternating day and night shifts, but no abnormal occurrence of these phenomena among those on permanent night work.This latter system then appears to be the best long-term policy, but meanwhile something may be done to relieve the strains of alternate day and night work by selecting those people who can adapt most quickly to the Changes of routinE.One way of knowing when a person has adapted is by measuring his body temperaturE.People engaged in normal day-time work will have a high temperature during the hours of wakefulness and a low one at night; when they change to night work the pattern will only adjust gradually back to match the new routine and the speed with which it does so parallels, broadly speaking, the adaptation of the body as a whole, particularly in terms of performancE.Therefore, by taking body temperature at intervals of two hours throughout the period of wakefulness it can be seen how quickly a person can adapt to a reversed routine, and this could be used as a basis for selection. So far; however, such a form. of selection does not seem to have been applied in practicE.Why is the question of 'how easily people can get used to working at flight' no mere academic one?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.

不定项选择 温度对保留的影响大。

未知题型 Many professions are associated with a particular stereotypE.The classic (1)_____ of a writer, for example, is (2)_____ a slightly crazy-looking person, (3)_____ in an attic, writing away furiously for days (4)_____ enD.Naturally, he has his favorite pen and note-paper, or a beat-up typewriter, (5)_____ which he could not produce a readable worD.Nowadays, we know that such images bear little (6)_____ to reality. But are they completely (7)_____? In the case of at least one writer, it would seem not. Dame Muriel Spark, who (8)_____ 80 in February, in many ways resembles this stereotypical 'writer'. She is certainly not (9)_____, and she doesn't work in an attiC.But she is rather particular (10)_____ the tools of her tradE.She insists on writing with a (11)_____ type of pen in a certain type of notebook, which she buys from a certain stationer in Edinburgh called James Thin. In fact, so (12)_____ is she that, if someone uses one of her pens by (13)_____, she immediately throws it away. And she claims she (14)_____ enormous difficulty writing in any notebook other than (15)_____ sold by James Thin. This could soon be a (16)_____, as the shop no longer stocks them, (17)_____ Dame Muriel's supply of 72-page spiral bound is nearly (18)_____.As well as her 'obsession' about writing materials, Muriel Spark (19)_____ one other characteristic with the stereotypical 'writer': her work is the most (20)_____ thing in her lifE.It has stopped her from marrying; cost her old friends and made her new ones, and driven her from London to New York to Rome, Today she lives in the Italian province of Tuscany with a frienD.A.drawingB.imageC.descriptionD.illustration

未知题型 According to the context, the word 'effluents' in ParA.1 is closest in meaning towastes.D.risks.

单项选择题 （ ）是一种最有效和最经济的策略形式。 A. 正面进攻 B. 包围进攻 C. 迂回进攻 D. 侧翼进攻