go through/over/across的区别?

go through :是穿过,指从物体内部穿过.如 go through the forests 穿越森林
go across ：为 渡过、越过,只从物体表面或外部经过 如He rowed the boat across the lake
go over ：越过,只越过界限等,如 Do not go over that line（别越过那条线）