Q23:

Because visual inspection cannot reliably distinguish certain skin discolorations from skin cancers, dermatologists at clinics have needed to perform tests of skin tissue taken from patients. At Westville Hospital, dermatological diagnostic costs were reduced by the purchase of a new imaging machine that diagnoses skin cancer in such cases as reliably as the tissue tests do. Consequently, even though the machine is expensive, a dermatological clinic in Westville is considering buying one to reduce diagnostic costs.

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Which of the following would it be most useful for the clinic to establish in order to make its decision?

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1. Whether the visits of patients who require diagnosis of skin discolorations tend to be shorter in duration at the clinic than at the hospital
2. Whether the principles on which the machine operates have been known to science for a long time
3. Whether the machine at the clinic would get significantly less heavy use than the machine at the hospital does
4. Whether in certain cases of skin discoloration, visual inspection is sufficient to make a diagnosis of skin cancer
5. Whether hospitals in other parts of the country have purchased such imaging machines

为何是D?为何C不对？

应该选C

题目说通过visual inspection不能reliably可靠地把skin discoloration和skin cancer

区分开来,也就是说无法确认到底是哪一种病.所以在clinic的人需要从患者身上提取skin

tissue来做测试.而在W医院,检测的成本降下来了,是因为买了一台新的机器,这台新机器

来检测skin cancer时和clinic拿skin tissue来做测试检测是一样可靠的,所以clinic诊

所也要买一台这个机器来减少测试的成本.

C说的是机器在诊所的使用会不会比在医院要少得多,担心的是买了机器,但是使用不多,结

果没有减少成本.C是对的.