listener 听众
VHF 甚高频，特高频
UHF 超高频
NTSC NTSC制式
PAL PAL制式
SECAM SECAM制式
to televise，telecast，television broadcasting 电视播送
colour television 彩色电视
closed-circuit television 闭路电视
telecommunication satellite 通信卫星
television set，television receiver 电视接收机，电视机
screen 屏幕
the small screen 小屏幕
channel selector 频道选择器
definition 清晰度
cathode-ray tube 阴极射线管
