1. 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.
2. Animals with a certain behavioral disorder have unusually high levels of aluminum in their brain tissue. Since a silicon-based compound binds to aluminum and prevents it from affecting the brain tissue, animals can be cured to the disorder by being treated with the compound.
The argument is based on which one of the following assumptions?
A. Animals with the disorder have unusually high but invariable levels of aluminum in their brain tissue.
B. Aluminum is the cause of the disorder rather than merely an effect of it.
C. Introducing the compound into the brain tissue has no side effects.
D. The amount of the compound needed to neutralize the aluminum in an animal’s brain tissue varies depending upon the species.
E. Aluminum is never present in normal brain tissue.
思路：本文开始没有明确指出谁是因，谁是果，只是表明两种相关联的现象。但是第二句话就假设high levels of aluminum是因，否则这个治疗就是是无效的，根据这个要求去寻找答案。
A. 文中没有提到的invariable levels of aluminum出现，与题无关。
C. 没有涉及side effects。
3. The stated goal of the government’s funding program for the arts is to encourage the creation of works of artistic excellence. Senator Beton claims, however, that a government-funded artwork can never reflect the independent artistic conscience of the artist because artists, like anyone else who accepts financial support, will inevitably try to please those who control the distribution of that support. Senator Beton concludes that government funding of the arts not only is a burden on taxpayers but also cannot lead to the creation of works of true artistic excellence.
Which one of the following is an assumption on which Senator Beton’s argument is based?
A. Most taxpayers have little or no interest in the creation of works of true artistic excellence.
B. Government funding of the arts is more generous than other financial support most artists receive.
C. Distribution of government funds for the arts is based on a broad agreement as to what constitutes artistic excellence.
D. Once an artist has produced works of true artistic excellence, he or she will never accept government funding.
E. A contemporary work of art that does not reflect the independent artistic conscience of the artist cannot be a work of true artistic excellence.
思路：本文关键是要把never reflect the independent artistic conscience of the artist和cannot lead to the creation of works of true artistic excellence联系起来，找出本质联系，只要存在关系independent artistic conscience of the artist包含true artistic excellence就可以证明文中的观点，因此要找出能表示此关系的答案。
E. 符合要求，注意如果答案意思是the independent artistic conscience of the artist是true artistic excellence的必要条件即可，当然是充要条件也可，万一题目变化答案我们只要把握这个原则即可。