Read the passage and choose the correct answer (A, B, C, or D) The search for alternative sources of energy has led in various directions. Many communities are burning garbage and other biological waste products to produce electricity. Converting waste products to gases or oil is also an efficient way to dispose of waste. Experimental work is being done to derive synthetic fuels from coal, oil shale and coal tars. But to date, that process has proven expensive. Other experiments are underway to harness - power with giant windmills. Geothermal power, heat from the earth, is also being tested.Some experts expect utility companies to revive hydroelectric power derived from streams and rivers. Fifty years ago hydroelectric power provided one third of the electricity used in the United States, but today it supplies only four percent. The oceans are another potential source of energy. Scientists are studying ways to convert the energy of ocean currents, tides, and waves to electricity. Experiments are also underway to make use of the temperature differences in ocean water to produce energy. *
1 điểm
Câu 21 Which is the best title of the passage  
A Efficient Ways of Disposing of Waste
B The Search for Alternative Sources of Energy
C The Use of Water Productions for Energy
D New Discoveries in Geothermal Power
Câu 22. Which of the following is NOT mentioned in the passage as an alternative source of energy? *
1 điểm
A Electricity
B Synthetic fuels
C Burning of garbage
D Geothermal power
Câu 23. According to the author, the impracticability of using coal, oil shale and coal tars as sources of energy is due to ___________ . *
1 điểm
A their being money consuming
B their being time consuming
C the scarcity of sources
D the lack of technology their being money consuming
Câu 24. The word “it” in the last paragrph refers to ____. *
1 điểm
A Electricity
B alternative source
C hydroelectric power
D the United States
Câu 25. What can be inferred from the last paragraph? *
1 điểm
A Alternative energy will come from a variety of sources
B All alterenative production of energy will be delivered from water.
C Hydroelectric power will be the main source of energy
D Synthetic fuels will be the principal source of alternative energy