turn 和介词on

问题描述:

turn 和介词on
The whole fury and might of the enemy must very soon be turned on us.
这里on怎么理解,是和turn搭配的吗?这句话怎么理解呢?

turn转向 on us 对着我们来
意思是:敌人强大猛烈的火力很快就要打倒我们头上了.