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问题 选择题

玻璃棒是常用的实验仪器，下列实验操作中，需要使用玻璃棒的是：（　　）

①过滤；

②实验室制氯气；

③稀释浓硫酸；

④用食盐配制50g溶质质量分数为5%的氯化钠溶液．

A．①和②

B．①③④

C．①

D．①②③④

答案

①过滤操作中用玻璃棒引流，故①选；

②实验室用浓盐酸和二氧化锰在加热条件下反应制备氯气，不用玻璃棒，故②不选；

③稀释浓硫酸时，常用玻璃棒搅拌，故③选；

④配制溶液时常用玻璃棒搅拌、引流，故④选．

故选B．

单项选择题

As Oil Declines, So does America


More than 100 years ago, America’s first great economic (26) abroad was spearheaded by its giant oil companies, notably John D. Rockefeller’s Standard Oil Company. These companies (27) powerful beachheads in Mexico and Venezuela, and later in parts of Asia, North Africa and, of course, the Middle East. (28) they became ever more dependent on the extraction of oil in distant lands, American foreign policy began to be (29) around acquiring and protecting US oil concessions in major (30) areas.
With World War Ⅱ and the Cold War, oil and US national (31) became thoroughly intertwined. After all, the United States had prevailed over the Axis (32) in significant part because it possessed vast reserves of domestic petroleum, while Germany and Japan lacked them, depriving their forces of vital (33) supplies in the final years of the war. As it happened, though, the United States was using up its domestic (34) so rapidly that, even before World War Ⅱ was over, Washington (35) its attention to finding new overseas sources of crude oil that could be (36) under American control. As a result, Saudi Arabia, Kuwait and a host of other Middle Eastern producers would become key US oil suppliers (37) American military protection.
There can be (38) question that, for a time, American domination of world oil production would prove a potent source of economic and military power. (39) World War Ⅱ, an abundance of cheap US oil spurred the (40) of vast new industries, including civilian air travel, highway construction, a (41) of suburban housing and commerce, mechanized agriculture, and plastics.

A. stayed B. kept C. remained D. contained

Abundant oil also underlay the global expansion of the country’s (42) power, as the Pentagon defended the world while becoming one of the planet’s great oil guzzlers. Its global dominion came to (43) on an ever-expanding array of oil-powered ships, planes, tanks and missiles. As long as the Middle East—and especially Saudi Arabia—served essentially as an American gas station and oil (44) a cheap commodity, all this was relatively painless. That is why the use of military force has been a (45) of American foreign policy since 1987.
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判断题

进入危险化学品库区的机动车辆应安装防火罩。机动车装卸货物后，不得在库内、库房、货场停放和修理。
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