The dog rubbed its back ____ the wall.
问题描述：
The dog rubbed its back ____ the wall.
答
against
作为介词用法如下
In a direction or course opposite to:
逆：与某个方向或过程相反：
row against the current.
逆水行舟
可以理解为有反作用力的过程
答
against
rub against 摩擦
小狗用它的背在墙上磨蹭
答
against,这句话的意思是这条狗的背在墙上蹭来蹭去.against有紧靠；倚；碰撞的意思.牛津字典上的原句是the cat rubbed itself against my legs,猫在我腿上蹭来蹭去.