请看此题

Appendicitis is potentially fatal; consequently, patients with symptons strongly suggesting appendicitis almost always have their appendix removed. The  appropriate surgery is low-risk but performed unnecessaril in about 20% of all cases. A new developed internal scan for apendicitis is highly accurate, producing 2 misdiagoses for every 98 correct diagnoses. Clearl, using this test, doctors can largely avoid unnecssary removals of the appendix without, however, performing any fewer necessar ones than before, since_______________--

a. the misdiagnoses produced by this test are always instances of attributin appredicitis to someone who does not, in fact, have it

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

...

c, d, and e are obviously out, you will choose a or b?

显然是A啊。

without, however, performing any fewer necessar ones than 中有个重要的词any.

要达到这一效果。则，题目中的2 misdiagoses (百分之二误诊)中，全部只能是没有ppendicitis病被误诊为有该病。否则，就是将由该病的人误诊为没有该病，也就有可能有performing necessar ones than before。

刚才看错了，应该选B.从语义上排除A