工人师傅在用方砖铺地时，常常打两个木桩，然后沿着拉紧的线铺砖，这样地砖就铺得整齐，这个事实说明的原理是（    ）。

The officials soon realized that, _________, things would get worse.

A．unless dealt with it properly

B．if not properly dealing with

C．unless properly dealt with

D．if dealt not properly with