Read the following passage and mark letter A, B, C or D on your answer sheet to indicate the correct word that best fits each of the numbered blanks. Rivers are one of the world's most important natural resources. Many cities are on large rivers, and (23)_______every country has at least one river that plays an important part in the lives of its people. Besides transportation, rivers (24) _______ food, water for crops, water to drink, and opportunities for recreation for people who live along their banks. And in order to get water for crops, engineers sometimes build a dam (25)_______a river and let the water become a lake behind the dam. Then people can use their water not only to irrigate fields but also to make electricity for homes and industries. However, the water often becomes (26) _______ when cities on river banks grow in size and the number of industries increases. We are learning that it is necessary to keep rivers clean if we want to enjoy the (27)_________of the natural resources. 23. A. many B. a lot C. plenty of D. almost 24. A. provide B. support C. assist D. create 25. A. over B. across C. among D. under 26. A. crowded B. overloaded C. polluted D. excited 27. A. interests B. benefits C. tips D. receipts Read the following passage and mark letter A, B, C or D on your answer sheet to indicate the correct word that best fits each of the numbered blanks. The natural environment includes all natural resources that are necessary for life: the air, the oceans, the sun and the land. Because they are vital for life, these resources must be protected from pollution and conserved. Ecologists study their importance and how to use them carefully. According to ecologists, resources are divided into two groups: renewable and non-renewable. When a resource is used, it takes some time to replace it. If the resource can be replaced quickly and easily, it is called renewable. If it cannot be replaced quickly and easily, it is called non-renewable. For example, grass for animals is a renewable resource. When cows eat the grass, the resource is used. If the soil is fertilized and protected, more grass will grow. Coal, however, is non-renewable because it takes millions of years to make coal. All fossil fuels are nonrenewable resources. 28. The natural environment consits of ______ A. the air and the land B. the oceans and the sun C. the sun and the land D. all natural resources 29. According to ecologists, there are ______resource groups. A. two B. three C. four D. five 30. If the resource can be ______, it is called renewable. A. burnt quickly B. replaced quickly C. divided properly D. used quickly 31. Grass for animals is a ______ resource. A. limited B. non-renewable C renewable D. clean 32. According to the passage, coal is non-renewable because it takes ______to make coal. A. hundreds of years B. thousands of years C. millions of years. D. billions of years