描述流行病学方法包括（）。

A.生态学研究

B.实验研究

C.横断面调查

D.病例对照研究

E.队列研究

Aristotle was one of those who could found a civilization, and while he thought of education as both a social value and an end in itself, he ascribed its chief importance (21) what might be considered a third basic concept of education: to train the mind to think, (22) what it is thinking about. The key is not (23) it knows but how it (24) any new fact or argument. "An educated man," Aristotle wrote in On the Parts of Animals, "should be able to (25) a fair offhand judgment as to the goodness or badness of the method used by a professor in his exposition. To be (26) is in fact to be able to do this."
The Aristotle view of education as a (27) has become the conventionally worthy answer today (28) college presidents and other academic leaders are asked what an education should be. An educated man, says Harvard President Bok, (29) a deep breath, must have a "curiosity in (30) the unfamiliar and unexpected, an open-mindedness in entertaining opposing points of view, (31) for the ambiguity that surrounds so many important issues, and a willingness to make the best decision he can in the fact of uncertainty and doubt."
This is an approach that appears to (32) more importance to the process of learning (33) to the substance of what is learned. The very old notion of the generalist who could comprehend all subjects has (34) been an impossibility. To make matters (35) more difficult, the fields of knowledge keep changing.

A. acquires B. transmitsC. evaluatesD. identifies