Roland: The alarming fact is that 90 percent of the people in this country now report that they
know someone who is unemployed.
Sharon: But a normal, moderate level of unemployment is 5 percent, with 1 out of 20 workers
unemployed. So at any given time if a person knows approximately 50 workers, 1 or more will
very likely be unemployed.

139. Sharon's argument relies on the assumption that
(A) normal levels of unemployment are rarely exceeded

(B) unemployment is not normally concentrated in geographically isolated segments of the
population
(C) the number of people who each know someone who is unemployed is always higher
than 90% of the population
(D) Roland is not consciously distorting the statistics he presents
(E) knowledge that a personal acquaintance is unemployed generates more fear of losing
one's job than does knowledge of unemployment statistics

答案是B,我的理解是Sharon的论点基于这样的assumption-----失业问题不是仅仅孤立地集中在失业人口上(还要看失业比例). 不知道这样理解对吗?

感觉很绕弯弯,我觉得得出结论的假设应该主要基于"if a person knows approximately 50 workers"