One important factor that affects the correctness of the results is that __________.
A、A. the old men tested may not have shown such cognitive decline
B、B. people surveyed ale all old
C、C. people taking part in this test came from all over the world
D、D. women live longer than men
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正确答案
试题解析
考查阅读技能,由第四段的“Those results could be improper because the studies involved older people, and women live longer than men…” 可以推出A正确。