For one acadeic year all the students ar a high school were observed. The aim was to test the hypothesis that studying more increased a student's chances of earning a higher grade. It turn out that the students who spent the most time studying did not earn grads as high as did many studnts who stuied less. Notheless, the researches conclued that the resuls of the observation supported the initial hypothesiss.
Whic one fo the following, if true, most helps to expalin why the researchers drew the conclusion descreibed above?
A The students who spent the most studying earned higher grads then did some students who studies for less time than the aveage.
C. In each courses, the more a student studied, the better his or her grade was in that course. 为什么A不对呢?我怎么觉得C只是重述了一遍结论? explain题的原则是什么?是不是当加强题来做? A怎么不能加强呢?