题目

海水中蕴藏着丰富的资源，海洋资源的利用具有广阔前景。 （1） Ⅰ．粗盐提纯 从海水中得到的粗盐常含Ca2＋、Mg2＋、SO42－等杂质，需要提纯后才能综合利用。粗盐提纯的步骤有：①加入过量的Na2CO3溶液；②加入过量的BaCl2溶液；③加入过量的NaOH溶液；④用适量盐酸调节溶液的pH等于7；⑤溶解；⑥过滤；⑦蒸发。正确的操作顺序是(填选项字母)。a．⑤②③①⑥④⑦ b.⑤①②③⑥④⑦ c.⑤②①③④⑥⑦ d.⑤③②①⑥④⑦ （2） 判断Mg2+已沉As the railroads and the highways shaped the American West in the past centuries, a new electrical generating(发电)and transmission (输送) system for the 21st century will leave a lasting mark on the West, for better or worse. Much of the real significance of railroads and highways is not in their direct physical effect on the scenery, but in the ways that they affect the surrounding community. The same is true of big solar plants and the power lines that will be laid down to move electricity around.The 19 th century saw land grants(政府拨地) offered to railroad companies to build the transcontinental railroads, leaving public land in between privately owned land. In much of the West, some of the railroad sections were developed while others remained undeveloped, and in both cases the landownership has presented unique challenges to land management. With the completion of the interstate highway system, many of the small towns, which sprang up as railway stops and developed well, have lost their lifeblood and died.Big solar plants and their power lines will also have effects far beyond their direct footprint in the West. This is not an argument against building them. We need alternative energy badly, and to really take advantage of it we need to be able to move electricity around far more readily than we can now.So trade-offs will have to be made. Some scenic spots will be sacrificed. Some species(物种) will be forced to move, or will be carefully moved to special accommodations. Deals will be struck to reduce the immediate effects.The lasting effects of these trade-offs are another matter. The 21st century development of the American West as an ideal place for alternative energy is going to throw off a lot of power and money in the region. There are chances for that power and money to do a lot of good. But it is just as likely that they will be spent wastefully and will leave new problems behind, just like the railroads and the highways.The money set aside in negotiated trade-offs and the institutions that control it will shape the West far beyond the immediate footprint of power plants and transmission lines. So let’s remember the effects of the railroads and the highways as we construct these new power plants in the West.小题1:What was the problem caused by the construction of the railways?A．Small towns along the railways became abandoned.B．Land in the West was hard to manage.C．Some railroad stops remained underused.D．Land grants went into private hands.小题2:What is the major concern in the development of alternative energy according to the last two paragraphs?A．The use of money and power.B．The transmission of power.C．The conservation of solar energy.D．The selection of an ideal place.小题3:What is the author’s attitude towards building solar plants?A．Disapproving.B．Approving.C．Doubtful.D．Cautious.小题4:Which is the best title for the passage?A．How the Railways Have Affected the WestB．How the Effects of Power Plants Can Be ReducedC．How Solar Energy Could Reshape the WestD．How the Problems of the Highways Have Been Settled