A. 先综合后对比 B. 对同度量因素加以固定 C. 分子分母研究对象的范围一致 D. 需要全面的资料 E. 以上都不对
A. which B. what C. somewhat D. something
A. on B. off C. up D. down
A. at B. to C. with D. about
A. and B. is C. enjoys D. does