Frazier and Mosteller propose not only that researchers limit data collection on individual patients but also that researchers enroll more patients in clinical trials, thereby obtaining a more representative sample of the total population with the disease under study. Often researchers restrict study participation to patients who have no ailments besides those being studied. A treatment judged successful under these ideal conditions can then be evaluated under normal conditions. Broadening the range of trial participants, Frazier and Mosteller suggest, would enable researchers to evaluate a treatment’s efficacy for diverse patients under various conditions and to evaluate its effectiveness for different patient subgroups. For example, the value of a treatment for a progressive disease may vary according to a patient’s stage of disease. Patients’ ages may also affect a treatment’s efficacy.

According to the passage, Frazier and Mosteller believe which of the following about medical research?

A.    It is seriously flawed as presently conducted because researchers overlook facts that are relevant to the subject of their research.

B.    It tends to benefit certain subgroups of patients disproportionately.

C.    It routinely reveals new variables in research on entirely new treatments.

D.    It can be made more accurate by limiting the amount of information researchers collect.

E.     It cannot be freed of the risk that significant variables may be overlooked.

答案：E。这个E我是明白的。但是不明白为什么B选项不正确。因为在全文的最后部分有这样的一段话：Broadening the range of trial participants, Frazier and Mosteller suggest, would enable researchers to evaluate a treatment’s efficacy for diverse patients under various conditions and to evaluate its effectiveness for different patient subgroups.这个难道没有暗示B是正确的吗？请nn多多指教哦：）

Only in research on entirely new treatments are new and unexpected variables likely to arise.可能

但是E中的significant也不对啊，文中只说是relevant

 the risk that researchers will overlook facts relevant to a study, Frazier and Mosteller contend that such risk, never entirely eliminable from research