People always interrupted his before he________what he was trying to day.

A．finishes

B．would finish

C．had finished

D．has finished

下列是一些引起人患寄生虫病的病原体，其中消化道有口有肛门的是(      )

A．肝片吸虫

B．华支睾吸虫

C．蛔虫

D．猪带绦虫