变压器的由哪些元件组成，各部分的作用是什么？
参考答案：
由器身和油箱组成。器身包括（铁芯，绕组，引线及分接开关）油箱包括（箱体，油枕及邮箱附件）及高低压套管。器身就不必说了，主要作用是承载，及保护内部元器件，和链接油箱就是用来放油的，油的作用是起到润滑、绝缘及散热。高低压套管属于引出装置。还有保护装置（呼吸器，瓦斯继电器，防爆管，压力释放阀，温度计）。
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| You may think that English dictionaries have been used for many, many centuries. In fact an English dictionary you 1 today wasn't made until the Qing Dynasty (清朝). Three men did most of the important 2 work on dictionaries. They spent nearly all their lives trying to 3 words for their dictionaries. For them, it was a wonderful journey. The largest dictionary in the world is Oxford English Dictionary. The 4 for this dictionary came from an important meeting in Britain in 1857. Twenty-two years later, Oxford University asked Murray to be the editor of its new dictionary. Murray had never been to 5 . At the age of fourteen, he left his village school in Scotland and taught himself while working in a bank. 6 he became a great teacher. After Oxford gave him the job, Murray had a small house 7 in his garden to do the work. Every morning, Murray got out of bed at five o'clock and 8 in the small house several hours before breakfast. Often he would work into the night. Murray hoped to finish the new dictionary in the years. But after five years, he was 9 adding (增加) words for the letter "A"! He worked on the dictionary 10 he was very old. Forty-four years later, in 1928, other editors finished the dictionary. | ||||
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除去下列物质中混有的杂质，所选用的试剂及操作方法均正确的是
| 物质 | 杂质 | 除杂质选用的试剂和操作方法 | |
| A. | H2 | HCl | 先通过NaOH溶液，再通过浓硫酸 |
| B. | KNO3 | Ba(NO3)2 | 加适量的Na2SO4溶液，过滤 |
| C. | CO2 | CO | 通入适量O2，点燃 |
| D. | CaCl2 | CaCO3 | 加入足量水溶解，过滤、洗涤、干燥 |