When we read newspapers, we often come across the word pollution.This word was not familiar to the people some decades ago.But now, it is a serious threat to us because.it means the poisoning of the air, seas, rivers and lands, which would do harm to our health.

　　我们看报的时候，经常会看到“污染”这个词。这个词对于几十年前的人来说并不熟悉。然而对于我们来说，它是一个严重的威胁，因为它意味着危害空气、海洋、河流和土地，进而对我们造成伤害。