NTSC、PAL、SECAM三大制式简介 NTSC、PAL和SECAM是全球三大主要的电视广播制式,这三种制式是不能互相兼容的,例如在PAL制式的电视上播放NTSC的视频,则影像画面将不能正常显示。下面分别对这三种制式进行简要介绍。NTSC、PAL、SECAM三大制式采用区域分布图一、NTSC(National Televison System Comm...【阅读全文】
B.People celebrate festivals because they don’t want to work.people’s activities on that day?1.What is the main idea of the text?D.Festivals have only four kinds of origins.2、Develop students’reading ability and let them learn different reading skills.C.Festiva...【阅读全文】