题目

Human facial expressions differ from those of animals in the degree ______ they can be controlled on purpose. A. with which          B. to which                 C. of which             D. for which   答案：B15．如图，在平行四边形ABCD中，AB=5，BC=8，∠ABC的角平分线交AD于E，F在AE上，且AF=3，BE与CF交于点G，则△EFG与△BCG面积之比是$\frac{1}{16}$．