Microwavesthattransmittelevisionsignalsalwaystravelinastraightline.Becausetheearthisrounditisimpossibletosendtelevisionsignalsoveralongdistance.Forexampleifwetriedtosendtelevisionsignalsdirectlyf

问题：Microwavesthattransmittelevisionsignalsalwaystravelinastraightline.Becausetheearthisrounditisimpossibletosendtelevisionsignalsoveralongdistance.Forexampleifwetriedtosendtelevisionsignalsdirectlyf

答案：↓↓↓

李连友的回答：

网友采纳　　答案：DCBA提示：1．参见文章第一句。2．Ifwewanttosendtelevisionsignalsaroundthesurfaceoftheearthwemustsendthemfrompointtopointbytherelaysystem.Onlandwecansetup...