Which of the following most logically completes the passage?
Appendicitis (inflammation of the appendix) is potentially fatal; consequently, patients with symptoms strongly suggesting appendicitis almost always have their appendix removed. The appropriate surgery is low-risk but performed unnecessarily in about 20 percent of all cases. A newly developed internal scan for appendicitis is highly accurate, producing two misdiagnoses for every 98 correct diagnoses. Clearly, using this test, doctors can largely avoid unnecessary removals of the appendix without, however, performing any fewer necessary ones than before, since ______.
the patients who are correctly diagnosed with this test as not having appendicitis invariably have medical conditions that are much less serious than appendicitis
the misdiagnoses produced by this test are always instances of attributing appendicitis to someone who does not, in fact, have it
all of the patients who are diagnosed with this test as having appendicitis do, in fact, have appendicitis
every patient who is diagnosed with this test as having appendicitis has more than one of the symptoms generally associated with appendicitis
the only patients who are misdiagnosed using this test are patients who lack one or more of the symptoms that are generally associated with appendicitis
感觉这道题主要是对doctors can largely avoid unnecessary removals of the appendix without, however, performing any fewer necessary ones than before的理解,我这个渣渣反反复复读了n遍才知道什么意思。这里的ones指代的是前面的surgery,就是说该切的都切了,切错的也是没得阑尾炎的,也就是大大避免了误切事件。如果有一个是有阑尾炎但是被诊断为没问题,那就是少切了,那就是跟without performing any fewer necessary ones相违背的,所以被误诊的必须是把没问题的看出了有问题的,选B。
还有two misdiagnoses for every 98 correct diagnoses,说明是100个被诊断为“有”阑尾炎的,98个是的确有,有2个是没有的看成了有,这也跟选项B相符。
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