Two genes BRCA1 and BRCA2 are linked to hereditary breast cancer. Therefore in order to decrease the annual number of mammogram tests administered across a population and to more accurately assess a woman's individual risk of breast cancer, all women should be tested for these genes.
Which of the following is the assumption?
A. Some women who are tested for the two genes will subsequently undergo mammograms on a less frequent basis than they used to.
B. The majority of breast cancer patients have no family history of the disease.
C. Researchers may have identified a third breast cancer gene that is linked with hereditary breast cancer.
D. Women who have these genes have an 80 pc chance of getting breast cancer while women who don't have these genes have only a 10 pc chance of getting breast cancer.
E. The presence of BRCA1 and BRCA 2 can explain upto to 50% of hereditary cases.
The correct answer is A.
Would anyone be kind enough to tell me WHY Answer choices D & E are WRONG. Many thanks in advance. 作者: DeliciaAn 时间: 2015-11-2 16:19
A. 取非－> 一些女人啊检查完这2个基因，仍旧像过去（或者比过去多）取进行mammograms. 与结论（1）相违背，削弱原文。选
D. 取非-> 这种陈述没办法取非，所以换个方法。女人有这两种genes得乳腺癌的可能是80%，没有这两种genes得乳腺癌得可能是10%。对结论要达到的目的没啥影响啊，所以这是个无关选项。实验内容不是实验带来的影响，这两者无关。
E. 取非-> B1和B2不能解释50％的遗传病例（或：解释50%以下的遗传病例）。这个选项并不能看出来是否达到了第二个目标（2）更精准的判断女人是否有得乳腺癌的风险。因为用的是more accurately,过去的数据是怎样的，题目没有给，所以更精准的判断，根据这个50％看不出来，以前如果只能判断20%，那么50%就达到了more accurately的效果；若以前是80%，那么这个genes的解释力度就变小了。所以这个assumption并不对结论以及结论想要达到的目的造成什么影响。所以也是无关选项。
