watch television是英文中多年沉积下来的一种习惯用法,常缩写成watch TV而watch movies 则要遵循一般规律了,movie是可数名词,所以不能单用看一部电影用watch a/the movie, watch one of my favorite movies强调看电影这个行为时用watch movies
television 不可数名词, 电视,电视节目如果你说 watch TV programmes 就要加S了