填空英语The earth is our home.We must take care of i.Pollution i

填空英语
The earth is our home.We must take care of i.Pollution is a "dirty"word.To pollute means to make things dirty.Today,we can see it,smell it and drink it.Pollution is not only harmful to our health but also to our life.
It is true that a_______pollution is still the most s_____now,but it is only one kind of pollution .Now bot water pollution and n______pollution have become two new kinds of pollution.