题目

如图是正方体的平面展开图，每个面上标有一个汉字，与“我”字相对的面上的字是( )A. 国 B. 厉 C. 害 D. 了 答案：【答案】A【解析】正方体的表面展开图，相对的面之间一定相隔一个正方形，根据这一特点作答．解：正方体的表面展开图，相对的面之间一定相隔一个正方形，与“我”字相对的面上的字为“国“。故选A.All too often , a choice that seems sustainable（可持续的）turns out on closer examination to be problematic. Probably the best example is the rush to produce ethanol（乙醇）for fuel from corn . Corn is a renewable resource ―you can harvest it and grow more, almost limitlessly. So replacing gas with corn ethanol seems like a great idea .One might get a bit more energy out of the ethanol than that used to make it, which could still make ethanol more sustainable than gas generally, but that’s not the end of the problem. Using corn to make ethanol means less corn is left to feed animals and people, which drives up the cost of food. That result leads to turning the fallow land ― including, in some cases, rain forest in places such as Brazil ― into farmland, which in turn gives off lots of carbon dioxide（CO2）into the air. Finally, over many years, the energy benefit from burning ethanol would make up for the forest loss. But by then, climate change would have progressed so far that it might not help.You cannot really declare any practice “sustainable” until you have done a complete lift-cycle analysis of its environmental（环境的）costs. Even then, technology and public policy keep developing, and that development can lead to unforeseen and undesired results. The admirable goal of living sustainable requires plenty of thought on an ongoing basis.57. What might directly cause the loss of the forest according to the text?A. The growing demand for energy to make ethanol.B. The increasing carbon dioxide in the air.C. The greater need for farmland.D. The big change in weather.58. The underline word “it” in the second paragraph refers to “              ” .A. the energy benefit               B. the forest lossC. climate change                  D. burning ethanol  59. The author thinks that replacing gas with corn ethanol is               .A. impractical   B. acceptable    C. admirable    D. useless 60. What does the author mainly discuss in the text?A. Technology.                   B. Sustainability.C. Ethanol energy.                D. Environmental protection.