求助几道加强题

1. There is a great deal of geographical variation in the frequency of many surgical procedures-up to tenfold variation per thousand between different areas in the numbers of hhysterectomies, prostatectomies, and tonsillectomies.

To support a conclusion that much of the variation is due to unnecessary surgical procedures, it would be most important to establish which of the following? 3个选项很容易排除,剩下2个

B. The variation is unrelated to factors (other than the surgical procedures themselves) that influence the incidence of diseases for which surgery might be considered;

D. For certain surgical procedures it is difficult to determine after the operation whether the procedures were necessary or whether alternative treatment would have secceeded.

我选择了D,我了解certain surgical procedures指示不明,但是我怎么都想不清楚B如何支持?

2. In Argonia the average rate drivers pay for car accident insurance is regulated to allow insurance companies to make a reasonable profit. Under the regulations, the rate any individual driver pay never depends on the actual distance driven by that driver each year. Therefore Arigonians who drive less than average partially subsidize the insurance of those who drive more than average.

The conclusion above would be properly drawn if it were also true that in Argonia:

A the average accident insurance rate for all drivers rises whenever a substantial number of new drivers buy insurances;

B the average cost to insurance companies of insuring drivers who drive less than the average is less than the average cost of insuring drivers who drive more than the annual average

C the lower the age of a driver the higher the insurance rate paid by that driver

D insurance company profits would rise substantially if drivers were classified in terms of the actual number of miles they drive each year

E drivers who have caused insurance companies to pay costly claims generally pay insurance rates that are equal to or lower than those paid by other drivers

这题我实在想不通.既然公里数少的司机补偿了公里数多的司机来保证保险公司的赢利,意思就是你付多少钱不取决于你开的公里数因此很显然不可能答案是B?

3. In Swartkans territory archeologists discovered charred bone fragements dating batck 1 million years. Analysis of the fragments which came from a variety of animals, showed that they had been heated to temperatures no higher than those produced in experimental camfiles made from branch of white stinkwood, the most common tree around Swartkans,

问下面哪个选项支持了the claim that the charred bone fragments are evidence of the use of fire by early hominids?

答案是:The bone fragments were found in several distinct layers of limestone that contained primitive cutting tools known to have been used by early hominids.实在想不通推理过程?

4. It is widely assumed that a museum is helped financially when a generous patron donates a protential exhibit. In truth, however, donated objects require storage place which is not free, and routine conservation which is rather expensive. Therefore such gifts exacerbate rather than lighten the demands made on a museum's financial resources. 问weaken

A. To keep patrons well disposed a museum will find it advisable to put at least some donated objects on exhibit rather than merely in storage

B. The people who are most likely to donate valuable objects to a museum are also people who are most likely to make cash gifts to it

C A museum can not save money by resorting to cheap storage under less than adequate conditions, because so doing would drive up the cost of conservation

D Patrons expect a museum to keep donated objects on its possession rather than to raise cash bu selling them

E Objects donated by a patron to a museum are often of such importance that the museums would be obliged to add them to its collection through purchase if necessary

答案E,我觉得E应该首先排除,如果博物馆要买下画来,那岂不是更加贵?我觉得B是weaken,

请高人指教,感谢!