Choose the correct word A, B or C for each gap to complete the following passage.

   Rivers are (1) ………… of the world’s most important natural resources. Many cities are on large rivers, and (2) ………….. every country has at least one river that (3) ………… an important part in the lives of its people.

   Besides transportation, rivers (4) ……….. food, water for crops, water to drink, and opportunities for recreation for people who live along their (5) ……….. And in order to get water for crops, engineers sometimes build a dam across a river and let the water become a lake (6) ………… the dam. Then people can use their water nit only to (7) ………… fields but also to make electricity for homes and industries.

   (8) ……………, the water often becomes polluted when cities on river banks grow (9) ………… size and the number of industries increases. We are learning that it is necessary to (10) ………….. rivers clean if we want to enjoy the benefits of the natural resource.

1. A. one

B. ones

C. among

D. those

2. A. most

B. mostly

C. almost

D. about

3. A. takes

B. makes

C. occupies

D. plays

4. A. supply

B. provide

C. distribute

D. bring

5. A. banks

B. shores

C. sides

D. beaches

6. A. behind

B. on

C. below

D. under

7. A. take

B. irrigate

C. drain

D. give

8. A. Moreover

B. Therefore

C. Thus

D. However

9. A. of

B. about

C. in

D. for

10. A. keep

B. get

C. hold

D. maintain