OG 93

sweetstar

请教：

93. Dental researchers recently discovered that tooth-brushes can become contaminated wth bacterial that cause pneumonia and strep throat. They found that contamination usually occurs after toothbrushes have been used for four weeks. For that reason, people should replace their toothbrushes at least once a month.

Which of the following, if true, would most weaken the conclusion above?

(A) The dental researchers could not discover why toothbrush contamination usually occurred only after toothbrushes had been used for four weeks.

(B) The dental researchers failed to investigate contamination of toothbrushes by viruses, yeasts, and other pathogenic microorganisms.

(C) The dental researchers found that among people who used toothbrushes contaminated with bacterial that cause pneumonia and strep throat, the incidence of these diseases was no higher than among people who used uncontaminated toothbrushes.

(D) The dental researchers found that people who rinsed their toothbrushes thoroughly in hot water after each use were as likely to have contaminated toothbrushes as were people who only rinsed their toothbrushes hurriedly in cold water after each use.

(E) The dental researchers found that, after six weeks of use, greater length of use of a toothbrush did not correlate with a higher number of bacterial being present. C

E为什么不对？

寂寞的声音

6个星期是4个星期以后，即便是 did not correlate with a higher number of bacterial being present 也不能说明在4个星期的时候没有很多的contamination, 不能weak研究人员的说法

hitlzc

以下是引用寂寞的声音在2005-9-6 11:12:00的发言：
6个星期是4个星期以后，即便是 did not correlate with a higher number of bacterial being present 也不能说明在4个星期的时候没有很多的contamination, 不能weak研究人员的说法

说的对，是无关的。

不过我也选成E了。