以同轴电缆传输视频信号的模拟传输方式，如果超过（），就必须对视频信号进行补偿放大。
A.50m
B.100m
C.150m
D.200m
参考答案：D
25. – Tom, it's too late. Our son ________ be back.
– Don't be anxious. I dare say he ________ have some extra work to do.
A．can; must
B．will; might
C．should; must
D．must; may
以下指标，（）不是品牌导入期所主要关注的指标。
A.消费者知晓率
B.消费者主动询问比例
C.消费者尝试比例
D.消费者重复购买率
