FF109. Several studies have shown that hospitals are not all equally successful: patients are much more likely to die in some of them than in others. Since the hospitals in the studies had approximately equal per-patient funding, differences in the quality of care provided by hospital staff are probably responsible for the differences in mortality rates.

Which one of the following, if true, casts the most doubt on the conclusion drawn above?

A. The staff in some of the hospital studies had earned more advanced degrees, on average, than the staff in the other hospitals.

B. Patient populations vary substantially in average severity of illness from hospital to hospital.

C. The average number of years that staff members stay on at a given job varies considerably from one hospital to another.

D. Approximately the same surgical procedures were performed in each of the hospitals covered in the studies.

E. Mortality rates for hospital patients do not vary considerably from one region of the country to another.

答案是﹙B﹚，但﹙D﹚那儿有问题呢?又题目中的” equally successful”指的是什么?

successful adjective

1 having the effect or result you intended

- The operation was successful.

- a highly successful (=very successful) meeting

successful in (doing) something

- Were you successful in persuading him to change his mind?

翻成成功 应该也说的过吧

D是support 不是weaken 手术过程一样(排除他因)

B每家医院重病的人口数有很大的差异---weaken

equally successful,

the author thinks since the hosiptals had equal per-patient funding, the quality of care provided to each patient should be equal. Therefore the mortality rates of hospitals should be equal too. But in reality, some of hopsitals had the higher rates, not equally successful.

To weaken the author's conclusion, we have to find another reasons for higher mortality rate.B provides an alternative reason: severity of illness.

the procedure of surgical has little connection to mortality rate.