Question

[Minh Vương Nguyễn Bá]

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 under way to harmless power with giant windmills. Geothermal power, heat from the earth, is also being tested. Some experts expect utility companies to revive hydroelectric 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 under way to make use of temperature differences in ocean water to produce energy.

1.     What provided one third of the electricity in the United State fifty years ago?

Fifty years ago, hydroelectric power provided one third of the electricity used in the United States________________

2.     What could best replace the phrase “geothermal power” in the passage?

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3.     Name three alternative sources of energy mentioned in the passage.

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4.     According to the author, what is the impracticability of using coat, oil shale and coal tars as sources of energy due to?

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5.     What is the best title of the passage?  ________________________________________