卡巴迪运动在亚洲哪一地区非常流行？
参考答案：
南亚。
— What are your students doing now?
— They football. Let's go and have a look.
A．are playing
B．will play
C．is playing
D．were playing
载波接受机的作用是接受发射出的载波频率的载波信号，并据此操作继电器执行任务。（）
