题目内容
国家贸易出现逆差时（）。
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With nuclear energy, the amount of pollution is greatly reduced. 【B6】______ the production of nuclear energy is based on the fission (裂变) of atoms, pollution is kept to a very low level. The energy produced in the reactors is converted into heat and electricity, and these have 【B7】______ or no pollution at all. Conventional forms of fuel, 【B8】______ , produce large amounts of pollution.
Production of nuclear energy uses the 【B9】______ of the fission of atoms; thus, 【B10】______ amounts of energy can be obtained from it. The world's reserves of oil, coal and natural gas are running 【B11】______ at a tremendous rate and current estimates predict that 【B12】______ of the 21st century, most of these conventional fuels will be used up. Nuclear energy is the exception 【B13】______ this gloomy prediction. Through splitting and fusing atoms, large amounts of energy can be produced, and 【B14】______ this process can go on and on until all our energy needs are satisfied. The 【B15】______ of nuclear energy as boundless source of energy is indeed great, and we must harness it whenever possible as conventional fuels will not be around much longer.
【B1】______
【B20】
【B18】
平仓盈亏结算是当日平仓的总值与原持仓合约总值的差额的结算。()
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