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

鞭虫卵形态中，哪项最具诊断价值( )

A．两端各具一透明塞状突起
B．黄褐色
C．内含一卵细胞
D．卵壳较厚
E．虫卵最小