Question

Rivers are one of our most important natural resources. Many of the world’s great _____31____ are located on rivers, and almost ____32_____ country has at least one river flowing through it that plays _____33_____ important part in the lives of its people.

   Since the beginning of history, people _____34_____ (use) rivers for transportation. The longest one in the United States is the Mississippi, and the lifeline of Egypt is the Nile. _____35_____ transportation, rivers give water to drink, water for crops, and chances for fun and recreation for the people ____36___ live along their banks.

   However, large cities and industries that are located on rivers often make problems. As the cities grow ____37_____ size and industries increase in number, the water in the rivers becomes _____38_____ (pollute) with chemicals and other materials. People are learning the _____39_____ (important) of doing more to keep their rivers clean ____40______ they want to enjoy the benefits of this natural resource.

Answer 1

31 cities                   32 every/each                 33 an                           34 have used/ have been using         35 Besides   

36 who/ that             37 in                              38 polluted                   39 importance                                40 if / because