66. B - "Beyond these simple and direct uses, those forms have not much adaptability.''
67. C - 'Steam was the first invention that replaced wind power. It was used to drive engines and was passed through pipes and radiators to warm rooms.'
68. C -
'On the other hand, we make use of electricity in thousands of ways. From the powerful voltages that drive our electric trains to the tiny current needed to work a simple calculator, and from the huge electric magnet in steel works that can lift 10 tons to the tiny electric magnet in a doorbell, all are powered by electricity. An electric current can be made with equal ease to heat a huge mass of molten metal in a furnace, or to boil a jug for a cup of coffee.'
69. C - máy phát điện
70. B - nước và than đá
71. B - thuỷ triều
72. A - 'From the powerful voltages that drive our electric trains to the tiny current needed to work a simple calculator, and from the huge electric magnet in steel works that can lift 10 tons to the tiny electric magnet in a doorbell, all are powered by electricity.'
73. A - không gây ô nhiễm
74. B xăng
75. D. Why Electricity is So Remarkable - Tại sao điện lại có tác động đáng kể như vậy