關於英文句型問題（二）。?

Like many other nations , mainland China also has air pollution problems. The government believes that if people know more about the problem , they will want to do something about it.
請問知識大大們，此句後段the problem為什麼不是用複數the problems呢？如果用複數the problems，那後面接得句子是不是要變成 they will want to do something about them.呢？謝謝：)