布氏姜片吸虫的主要保虫宿主是()

A．啃齿动物

B．肉食动物

C．反鱼类动物

D．猪

E．飞禽类

Nancy hasn’t begun on her PH.D ________ working on her master’s degree.

A. still because she is yet

B yet as a result she is still

C yet because she is still

D still while she is already