The University of Illinois experiment was different from previous studies in that______. A．its researchers categorized the children only by fitness levels B．it highlighted the importance of students' running on a treadmill C．it showed how being fit affects children's performance on the tests D．it asked the subjects to complete tests that were beyond their levels
A. A．its B.it C.it D.it
【参考答案】
C 解析：根据题干中的previous studies将本题出处定位到第3段前3句。这几句提到，以前的研究已经发......