题干

下列关于氧气的说法中错误的是(   )

A:氧气在低温、高压的条件下可以转化为液体或者固体

B:氧气的重要来源是植物光合作用

C:氧气的化学性质比较活泼,是可燃物

D:因为氧气与氮气的沸点不同,所以工业上用分离液态空气法制取氧气

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答案(点此获取答案解析)

C

同类题1

阅读理解

    No country in the world has more daily newspapers than the US. There are almost 2,000 of them, as compared with 180 in Japan, 164 in Argentina and 111 in Britain. The quality of some American papers is extremely high and their views are quoted all over the world. Famous dailies like the Washington Post or the New York Times have a powerful influence all over the country. However, they are not national newspapers in the sense that The Times is in Britain or Le Monde is in France, since each American city has its own daily newspaper. The best of these presents detailed description of national and international news, but many tend to limit themselves to state or city news.

    Like the press in most other countries, American newspapers range from the “sensational” which feature crime and gossip (闲谈), to the “serious”, which focus on factual news and the analysis of world events. But with few exceptions, American newspapers try to entertain as well as give information, for they have to compete with the attraction of television.

    Just as American newspapers satisfy all tastes, so do they also try to attract readers of all political parties. A few newspapers support extremist (极端主义的) groups on the far right and on the far left, but most daily newspapers try to attract middle-of-the-road Americans who are moderate (中立的). Many of these papers print columns by well-known journalists of different political and social views, in order to present a balanced picture.

    As in other countries, American newspapers can be either responsible or irresponsible, but it is generally accepted that the American press serves its country well and that it has more than once courageously exposed political scandals (丑闻) or crimes, for instance, the Watergate Affair (水门事件). The newspapers drew the attention of the public to the horrors of the Vietnam War.

同类题2

阅读理解
    Octopuses (章鱼) are sea animals famous for their rounded bodies, bulging eyes, and eight long arms. They live in all the world's oceans but there are especially more octopuses in warm, tropical (热带的) waters. Octopuses, like their cousin, the squid (乌贼), are often considered “monsters of the deep”, though some species, or types, occupy relatively shallow waters.
    Most octopuses stay along the ocean's floor, although some species are pelagic, which means they live near the water's surface. Other octopus species live in deep, dark waters, rising from below at dawn and dusk to search for food. Crabs and shrimps rank among their favorite foods, though some can attack larger prey (猎物), like sharks. Octopuses typically drop down on their prey from above and, using powerful suctions that line their arms, pull the animals into their mouths. The octopus performs its famous backward swim by blowing up water through a muscular tube on the body called a siphon. Octopuses also crawl (爬) along the ocean's floor, putting their arms into small openings to search for food Seals, whales, and large fish prey on octopuses.
    If threatened, octopuses shoot an inky liquid that darkens the water, confusing the other animals. The octopus can also change to gray, brown, pink, blue, or green to mix with its surroundings. Octopuses may also change color as a way to communicate with other octopuses. Octopuses are solitary creatures that live alone in dens (巢穴) built from rocks, which the octopus moves into place using its powerful arms. Octopuses sometimes even fashion a rock “door” for their dens that pull closed when the octopus is safely inside.

同类题4

某小组进行“探究培养液中酵母菌种群数量的动态变化”实验时,同样实验条件下分别在4个试管中进行培养(见下表),均获得了“s”型增长曲线。根据实验结果判断,下列说法错误的是( )   
   试管号
    I
   Ⅱ
   Ⅲ
   Ⅳ
   培养液体积(mL)
    10
    5
    10
    5
 起始酵母菌数(103个)
    10
    5
    5
    10