① Obviously, MP⊥AB, NQ⊥AB, P and Q are all vertical feet.

② When the car travels from A to B, it will be separated from M at the AP section. The distance of n has been decreasing and the influence is increasing.

When the car travels from a to b, it leaves m, The distance of n has been increasing, and its influence is getting smaller and smaller.

When the car travels from A to B, the distance from M on PQ section increases, and the influence becomes smaller and smaller. The distance from n has been decreasing. The influence on n village is gradually increasing.