Видовременные формы глагола. Действительный и страдательный залог Контрольная

The Mississippi River is one of the largest rivers in the world. It affects the life of millions of people living along its banks and the banks of its tributaries. One hundred and twenty years ago it was a great road for paddlewheel streamers and giant log rafts. Small boys swam in its waters and people drank the Mississippi River water without filtering it or adding chemicals to purify it. At that time the Mississippi was regarded as an unlimited source of fresh, pure water.

Today, that picture has changed. In addition to the natural pollution from the mud that is washed into the river, there are now thousands of tons of wastes from sewage disposal plants and industrial plants being poured into the water.

Pollution is basically a product of people. Men have always thrown their waste products into the waters. Today, however, there are so many industries and so many people that the old-fashioned methods of disposing of wastes do not work any longer. The Mississippi has had so much filth dumped into it that people all along the river are feeling the ill effects of the pollution. 

Perhaps the most dangerous effect of the polluted river is the effect on the water supplies of the people living near it. Most of the towns and cities on the Mississippi draw their water from the river. The more pollutants or wastes, added to the river, the more chemicals added to the water supply to purify it.

The result of this situation is that the drinking water is a chemical soup.