GWD21-Q33

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 by 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 cells can absorb

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

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

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

key is B, can sb translate the last sentence into chinese? thx

能不能解释一下这道题？

顺便说一下，这题感觉好奇怪啊~是BF题吗？好像又不太像。。。

这是boldface和support题目相结合

首先要判断boldface的作用，support main conclusion

其次，就是寻找同样support的evidence，一石二鸟

这个题的关键点是 肌肉从血液中吸收的氧气

削弱这个，一是，只有通过肺

二是  血液中的氧气已经足够肌肉吸收了，达到饱和状态了