这俩是近义词 都是副词,没有太大的区别,意思都是moving from one place to another and back again,或者from side to side.要非说有区别的话（说真的,区别不大）,我个人认为backward and forward 可以用来借喻或者说是比喻.例如：the lawyer argued the point backwards and forwards for an entire week.