When television first began to expand, very few of the people whohad become famous as radio commentators were equally effective on television.Some of the  __1__ they experienced when they were trying to  __2__ themselves to the newmedium were technical. When working __3__ radio, for example, they had become  __4__ toseeing on  __5__ of the listener. This __6__ of seeing for others means that the __7__ hasto be very good at talking. __8__ all, he has to be able to __9__ a continuous sequenceof visual images which __10__ meaning to the sounds which the listener hears. Inthe __11__ of television, however, the commentator sees __12__ with the viewer. His role,therefore, is __13__ different. He is there to make __14__ that the viewer does not __15__ some points of interest, to help him __16__ on particular things, and to __17__ theimages on the television screen. __18__ his radio colleague, he must know the __19__ ofsilence and how to use it at those moments __20__ the pictures speaks forthemselves.