"TELLING us the merits of a certain shamopp"做TV screen的定语,修饰TV screen.ING分词和ED分词都可以引导从句做定语的.因为本身就可以看做形容词做定语.
严格说应该是but then a large TV screen jumps into life TELLING us the merits of a certain shamopp.=but then a large TV screen jumps into life which tells us the merits of a certain shamopp.