2. 外语
  3. Seafood could be going off a lot of menus as the world warms. More than half of a group of fish【C1】______ for the marine food we

Seafood could be going off a lot of menus as the world warms. More than half of a group of fish【C1】______ for the marine food we

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问题     Seafood could be going off a lot of menus as the world warms. More than half of a group of fish【C1】______ for the marine food web might die if, as 【C2】______, global warming reduces the amount of oxygen【C3】______ in some critical areas of the ocean—including some of our richest fisheries.
    The prediction【C4】______a unique set of records that goes back to 1951. California has regularly【C5】______ its baby fish to support the sardine fishery. "There is almost no other dataset going back so far that【C6】______every kind of fish," says Tony Koslow of the Scripps Institution of Oceanography in La Jolla, California, who heads the survey. The survey records also include information 【C7】______ water temperature, the 【C8】______proportion of salt in a solution and the dissolved oxygen content.
    Koslow’s team studied records of 86 fish species found【C9】______ in the samples and discovered that the abundance of 27 of them【C10】______ strongly with the amount of oxygen 200 to 400 metres down; a 20 percent drop in oxygen meant a 63 percent drop in the fish. There have been several【C11】______of low oxygen during the period【C12】______, mainly in the 1950s and since 1984. Global climate models predict that 20 to 40 percent of the oxygen at these depths will disappear over the next century 【C13】______ wanning, says Koslow— mainly because these waters get oxygen by mixing with【C14】______ waters. Warmer, lighter surface waters are less likely to mix with the colder, denser waters【C15】______.
    Of the 27 species most【C16】______ by low oxygen, says Koslow, 24 were fish that spend the daytime in deep, dark waters below 200 metres to【C17】______ predators that hunt by【C18】______. There are 10 billion tonnes of fish globally—10 times the annual global commercial【C19】______—and they are a vital food for other fish and【C20】______ birds and mammals.
【C11】
选项 A、episodes
B、chapters
C、parts
D、sections
答案A
解析 名词辨析题。句意为：在整个研究阶段，尤其是20世纪50年代和1984年以来曾出现过几次海水中含氧量低的阶段。四个选项中，[A]episodes“插曲，某一特定阶段”，可以用来表示“某一时期”，故为答案。[B]chapters多用于指书中的章节，与时间无关；[C]parts“部分，零件”；[D]sections“部分，段，章节”，均不符合题意，故排除。
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