阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。
Water is very important for living things. All animals and plants peed water. Man also needs water. All of us can't live (1)        (with) water.
Today most water sources (2)        dirty that people must purify water before (3)        (drink). Water becomes dirty in many ways. Industrial pollution is one of (4)        (they).With the (5)        (develop) of industry,plants and factories pour tons of industrial waste into rivers every day. The rivers have become (6)        (serious) polluted.The same thing has also happened to the seas and oceans. So the problem of water pollution is almost worldwide. Scientists of many (7)        (country) have done a lot of work to deal (8)        pollution. The (9)        (pollute) water in some places has become clean and drinkable again. If all of us do as much (10)        we can to protect water from pollution,people in all towns and cities will have clean water to drink again.