Community cancer dusters are viewed quite differently by citizen activists and by epidemiologists. Environmentalists and concern

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问题     Community cancer dusters are viewed quite differently by citizen activists and by epidemiologists. Environmentalists and concerned local residents, for instance, might immediately suspect environmental radiation as the culprit when a high incidence of cancer cases occurs near a nuclear facility. Epidemiologists, in contrast, would be more likely to say that the incidences were "inconclusive" or the result of pure chance. And when a breast cancer survivor, Lorraine Pace, mapped 20 breast cancer cases occurring in her West Islip, Long Island, community, her rudimentary research efforts were guided more by hope—that a specific environmental agent could be correlated with the cancers—than by scientific method.
When epidemiologists study clusters of cancer cases and other noncontiguous conditions such as birth defects or miscarriage, they take several variables into account, such as background rate (the number of people affected in the general population) , duster size, and specificity (any notable characteristics of the individual affected in each case). If a cluster is both large and specific, it is easier for epidemiologists to assign blame. Not only must each variable be considered on its own, but it must also be combined with others. Lung cancer is very common in the general population. Yet when a huge number of cases turned up among World War II shipbuilders who had all worked with asbestos, the size of the cluster and the fact that the men had similar occupational asbestos exposures enabled epidemiologists to assign blame to the fibrous mineral.
    Although several known carcinogens have been discovered through these kinds of occupational or medical clusters, only one community cancer duster has ever been traced to an environmental cause. Health officials often discount a community’s suspicion of a common environmental cause because citizens tend to include cases that were diagnosed before the afflicted individuals moved into the neighborhood. Add to this is the problem of cancer’s latency. Unlike an infectious disease such as cholera, which is caused by a recent exposure to food or water contaminated with the cholera bacterium, cancer may have its roots in an exposure that occurred 10 to 20 years earlier.
    Do all these caveats mean that the hard work of Lorraine Pace and other community activists is for nothing? Not necessarily. Together with many other reports of breast cancer clusters on Long Island, the West Islip situation highlighted by Pace has helped epidemiologists lay the groundwork for a well-designed scientific study.
The word "caveats" (in the last paragraph) refers to______.

选项 A、refusals by epidemiologists to examine the work of Pace and other activists
B、potential flaws in amateur studies of cancer cluster
C、warnings by activists concerning environmental dangers in their communities
D、tendencies of activists to assume environmental causes for cancer

答案B

解析 B意为:业余研究癌症患病群体的人可能犯的错误。caveat原意为“防止错误解释的说明”。这里指错误的解释。这句话的意思是:这些错误解释(指上一段提到的情况)是否意味着其他社会活动家花了很大力气做的研究都毫无意义呢?C项为干扰项,All these caveats实质上是忽略考虑环境的因素,这是专家的失误,而不是社会活动家针对群体面对的环境危险发出的警告。
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