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Rivers are one of our most important
natural resources. A n{#blank#}1{#/blank#} of the world's great cities are located on
rivers, and almost each country has at least one river f{#blank#}2{#/blank#} through it that p{#blank#}3{#/blank#} an important part in the lives of its people.
Since the beginning of history, people have
been using rivers for transportation. The longest one in the United States is
the Mississippi, and the lifeline of Egypt is the Nile. A{#blank#}4{#/blank#} from transportation, rivers give water to
drink, water for crops, and chances for fun and recreation for the people who
live along their banks.
However, large cities and industries that
are located on rivers often make problems. As the cities grow in size and
industries increase in number, the water in the rivers becomes p{#blank#}5{#/blank#} with chemicals and other harmful materials.
Experts a{#blank#}6{#/blank#}that environmental organizations should
work together with different communities and countries to find solutions to the
serious environmental problem. As c{#blank#}7{#/blank#} of the Earth, we all have a
responsibility to preserve and sustain the environment we have-for ourselves
and our future generations. After all, there is no s{#blank#}8{#/blank#} for our Earth. It's all we've got to live on.
