专升本考试

根据网考网考试中心的统计分析，以下试题在2019/6/20日专升本考试习题练习中，答错率较高，为：57%
【单选题】The trainer usually gives the animal a piece of candy or fruit ______.


A．when it is hungry
B．before it plays a trick
C．when it starts to play a trick
D．after it has done the trick