21-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 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

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 (B)

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

however 用在那里挺别扭？？

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GWD 21-33

One of the limiting factors in human physical performance is the amount of oxygen that is absorbed by the muscles from the bloodstream. Accordingly, entrepreneurs have begun selling at gymnasiums and health clubs bottles of drinking water, labeled “SuperOXY,” that has extra oxygen dissolved in the water. Such water would be useless in improving physical performance, however, since the only way to get oxygen into the bloodstream so that it can be absorbed bye the muscles is through the lungs.

Which of the following, if true, would serve the same function in the argument as the statement in boldface?

A. the water lost in exercising can be replaced with ordinary tap water

B. the amount of oxygen in the blood of people who are exercising is already more than the muscle can absorb

C. world-class athletes turn in record performance without such water

D. frequent physical exercise increases the body’s ability to take in and use oxygen (A)

E,lack of oxygen is not the only factor limiting human physical performance

I think the right key shoud be B rather A?

21-4: B is ok, however here just means the scan can decrease the unnecessary cases but does NOT decrease the necessary cases in the meantime.

21-33: agree wtih u, A is irrelevant.