—I think English is ______ than math.

—Why do you think ______? [ ]

A. much easier; that

B. much more easy; so

C. much easier; so

D. more easier; that

目前中国的制药研发主要是以（）为中心

A.政府部门

B.制药企业

C.科研单位

D.医疗机构