1.Human facial expressions differ from those of animals in the degree___B__they can be controlled on purpose.
问题描述：
1.Human facial expressions differ from those of animals in the degree___B__they can be controlled on purpose.
A.with which B.to which C.of which D.for which
why choose "to which"
答
这是一句定语从句
to which中的which是指human
句中的they是指表情
后半句就是对于人类来说,表情是可以被刻意控制的
至于用to不用for,那就看to sb./sth.和for sb./sth.的区别：
to一般翻译成“对于”,强调动作的对象；
for一般翻译成“为”,强调动作的受益者