8. Blood banks will shortly start to screen all donors for NANB hepatitis. Although the new screening tests are estimated to disqualify up to 5 percent of all prospective blood donors, they will still miss two-thirds of donors carrying NANB hepatitis. Therefore, about 10 percent of actual donors will still supply NANB-contaminated blood.
The argument above depends on which of the following assumptions?
(A)Donors carrying NANB hepatitis do not, in a large percentage of cases, carry other infections for which reliable screening tests are routinely performed.
(B) Donors carrying NANB hepatitis do not, in a large percentage of cases, develop the disease themselves at any point.
(C) The estimate of the number of donors who would be disqualified by tests for NANB hepatitis is an underestimate.
(D) The incidence of NANB hepatitis is lower among the potential blood donors than it is in the population at large.
(E) The donors who will still supply NANB-contaminated blood will donate blood at the average frequency for all donors.
我再看题时发现了我的错误
C：我当时错误的将“estimated to disqualify up to 5 percent of all prospective blood donors”与 “they will still miss two-thirds of donors carrying NANB hepatitis”分开来理解，其实这句话都是ESTIMATED的内容，所C选项其实是削弱。
我同意选A，但理解与你不同，它的意思是“这些Donors carrying NANB hepatitis 不会携带其他传染病而被其它常规检查检测出不合格。因为如过是，被遗漏的Donors carrying NANB hepatitis 就不到10%”作者: z_weining 时间: 2002-10-29 22:42
