We all know that the normal human daily cycle of activity is of some 7—8 hours’ sleep alternation with some 16—17 hours’ wakefulness and that, broadly speaking, the sleep normally coincides with (与一致) the hours of darkness. Our present concern is with how easily and to what extent this cycle can be modified.
The question is no more an 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 (发生率) of disturbed sleep and other disorders among those on alternating day and night shifts, but no abnormal occurrence of theses 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 alternative day and night work by selecting those people who can adapt most likely to the change of routine. One way of knowing when a person has adopted is by measuring his body temperature. People engaged in normal daytime 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 gradually go 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.
66. By saying “The question is no more an academic one”, the author want to say______.
A. many people like to change the cycle of sleeping and working
B. sleeping normally coincides with the hours of darkness
C. automation calls for people to change their sleeping habits
D. changing people’s sleeping and working pattern is not easy.
67. The main problem of the round-the- clock working system lies in ___________.
A. the inconvenience caused by the automation to the workers
B. the disturbance of changing the cycle too frequently
C. the lack of working efficiency on night shifts
D. the difficulty finding a number of good night workers
68. The best remedy for the disorders among the alternating working-time workers seems to be__________.
A. changing the round-the-clock working system
B. allowing the night-shift workers to sleep more efficiently
C. employing people who work on night shifts only
D. making a more flexible working schedule for night workers
69. Which of the following statements can conclude the passage?
A. The change of body temperature as an indication of a worker’s performance.
B. The possible solutions to the problems of the round-the-clock working system.
C. Easy ways to adapt the body temperature to the changes of the night shifts.
D. Less disturbance to those who alternate day and night shifts at a longer interval.