单选题 The human body secretes more pain-blocking hormones late at night than during the day. Consequently, surgical patients operated on at night need less anesthesia. Since larger amounts of anesthesia pose greater risks for patients, the risks of surgery could be reduced if operations routinely took place at night.
Which of the following, if true, argues most strongly against the view that surgical risks could be reduced by scheduling operations at night?

A、 Energy costs in hospitals are generally lower at night than they are during the day.
B、 More babies are born between midnight and seven o'clock in the morning than at any other time.
C、 Over the course of a year, people's biological rhythms shift slightly in response to changes in the amounts of daylight to which the people are exposed.
D、 Nurses and medical technicians are generally paid more per hour when they work during the night than when they work during the day.
E、 (E) Manual dexterity and mental alertness are lower in the late night than they are during the day, even in people accustomed to working at high.

【正确答案】 E

【答案解析】[解析] 明晰问题目的永远是解题时最重要的，而这个问题目的是让我们找一个能反对在夜间进行手术能减少surgical risks的选项，因此选项应与surgical risks有关。(E)指出人们在夜间手术的灵巧性与精神警觉性更差，从而可能会提高surgical risks，所以(E)正确；而(A)、(B)、(C)、(D)均与surgical risks无关。