GWD 21,看了讨论，有点不明，求教

GWD21-Q4:

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 ______.

    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 ______.

 A.      the patients who are correctly diagnosed with this test as not having appendicitis invariably have medical conditions that are much less serious than appendicitis

 A.      the patients who are correctly diagnosed with this test as not having appendicitis invariably have medical conditions that are much less serious than appendicitis

B.       the misdiagnoses produced by this test are always instances of attributing appendicitis to someone who does not, in fact, have it

C.      all of the patients who are diagnosed with this test as having appendicitis do, in fact, have appendicitis

D.      every patient who is diagnosed with this test as having appendicitis has more than one of the symptoms generally associated with appendicitis

E.       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   B

题目说，1. 老方法造成20％做阑尾手术的人是误诊的（其实不需要做）

2. 新方法在98％正确诊断的基础上只有2例是误诊

3. 结论是说，使用新方法，可以避免不需要做的手术，同时需要做的手术没有比以前减少

B说，这个误诊是把有病的当作没病的
   è
   没有多做不必要的手术

可是题目里说需要做的手术没有比以前减少啊，按照B所说的岂不是减少了？

B:the misdiagnoses produced by this test are always instances of attributing appendicitis to someone who does not, in fact, have it

这种测试带来的误诊是通常认为没有阑尾炎的人患了阑尾炎

就是把没病的看成有病的。所以需要做的手术就应该是比以前增加了，题目中说没有减少，是对的

B:the misdiagnoses produced by this test are always instances of attributing appendicitis to someone who does not, in fact, have it

 2%误诊都属于没必要做的手术 (满足前提说的误诊里没有包括需要手术但没做的情况）

原来的方法理有20%误诊属于没必要做的手术

2%《20%

所以没必要做的手术的却减少了，B正确

我也和你有同样的疑问