Throughout history, man has developed sources of energy to do his work. Primitive man had only the strength of his arms and the use of fire. He later (46) how to use the energy of the wind to move his sailing vessels. He used the energy of water to (47) his mills. He tamed animals as new sources of energy. They pulled plows and wagons. A new stage in the development of the use of energy came with the (48) of steam engine. Steam could be used to develop energy to run machines. The discovery of electricity created an even more important way of using energy. So did the invention of gasoline engines. Man entered into a new (49) of the use of energy with the application of nuclear energy. Man finds many ways to release energy to do work. (50) , he changes the energy in a waterfall into electricity. He can turn this electrical current into radio waves that can carry his ideas for thousands of miles. He can release the energy in gasoline by burning it and using it to (51) automobiles. He can (52) use of coal to turn water into steam and, in return, use the steam to generate electrical energy. The nucleus of certain atoms can produce millions of times more energy per pound of material than can be made (53) by chemical means. 46. A. found B. showed C. discovered D. distinguished 47. A. turn B. take C. cycle D. move 48. A. finding B. production C. construction D. invention 49. A. time B. era C. history D. step 50. A. For example B. However C. As a result D. Nevertheless 51. A. equip B. provide C. feed D. power 52. A. make B. get C. take D. have 53. A. usable B. available C. possible D. capable giúp mình với. toàn bộ là trắc nghiệm thôi