共用题干 Sharks Perform a Service for Earth's WatersIt is hard to get people to think of sharks as anything but a deadly enemy. They are thought to1people frequently. But these fish perform a2service for earth's waters and for human beings. Yet business and s

题目
共用题干
Sharks Perform a Service for Earth's Waters
It is hard to get people to think of sharks as anything but a deadly enemy. They are thought to1people frequently. But these fish perform a2service for earth's waters and for human beings. Yet business and sport fishing are threatening their3.Some sharks are at risk of disappearing from4.
Warm weather may influence both fish and shark activity. Many fish swim near coastal areas5their warm waters. Experts say sharks may follow the fish into the same areas,6people also swim. In fact,most sharks do not purposely charge at or bite humans. They are thought to mistake a person7a sea animal,such as a seal or sea lion. That is why people should not swim in the ocean when the sun goes down or comes up.Those are the8 when sharks are looking for food. Experts also say that bright colors and shiny jewelry may cause sharks to attack.
A shark has an extremely good sense of smell. It can find small amounts of substances in wa-ter,such as blood,body liquids and9 produced by animals. These powerful10help sharks find their food. Sharks eat fish,any11sharks,and plants that live in the ocean.
Medical researchers want to learn more about the shark's body defense,and immune 12against disease. Researchers know that sharks13quickly from injuries. They study the shark in hopes of finding a way to fight human disease.
Sharks are important for the world's14.They eat injured and diseased fish. Their hunting activities mean that the numbers of other fish in ocean waters do not become too15.This protects the plants and other forms of life that exist in the oceans.

3._________
A: source
B: existence
C: friends
D: fish

相似考题
参考答案和解析
答案:B
解析:
本题应选择attack,因为第一句提到:人们认为鲨鱼是a deadly enemy,也就是说些鱼会对人类造成伤害。第二句是对deadly enemy的具体说明。其他的三个选项meet , love , visit 都不合适,love与上下文意思相反,meet和visit与上下文意思不符。所以答案为A。
空格2所在的句子由but连接,所以该句子表达的意思一定与第二句相反。第二句对置鱼的评价是负面的,填入空格2的词应该是正面的。四个选项中只有C项valua- ble符合这一条件,所以C项是答案。
第三句提到笠鱼有益于waters and human beings,第五句又提到鲨鱼濒临灭绝的危险。根据上下文的意思,threatening“威胁”到它们的应该是existence“生存”。其他的三个选项source , friends , fish都不合适,与上下文意思没有联系。所以答案为B。
如果置鱼消失,从什么地方消失呢? 当然从earth“地球”上消失。从space “宇宙空间”、sky“天空”中消失,或从1and“ 陆地”上消失,都有悖常理。所以答案为D。
四个选项的意思都是“因为”,但是从用法上分析,because、 since和by rea- son that之后要接句子,because of之后接名词或名词短语。their warm waters是名词短语,所以要选用C项because of。
... people also swim明显是定语从句,其先行词是表示地点的名词area,所以要选关系副词where。所以答案为D。
从上下文判断,本句的意思是:置鱼将人错认为是海洋动物。而“将……错认为是”的英语表达是mistake...for,所以本题的答案是B项。
本段的意思是:置鱼并非故意袭击人类。人们认为,由于置鱼将人错认为是海狮等海洋动物,在饥俄时才袭击人类。日出和日落时,正是鳌鱼饥肠辘辘的时候,人们不应该出海游泳。空格8填入的词应该与时间有关,所以times是答案,而与地点有关的选项 places , seas , oceans与上下文意思脱节。所以答案为A。
本段第一、二句提到置鱼的嗅觉特别灵敏,能嗅到海水中存在的极为微量的气味。作者举了三个物质:血、体液和化学品。空格9要填入表示物质的名词。四个选项中唯一表达物质的词是chemicals“化学品”。所以C项chemicals是答案,而其他三个选项与学科有关,脱离了上下文的意思,不是本题的答案。
在第一、二句意思的基础上,作者进一步说明,灵敏的嗅觉有助于鲨鱼找到食物。所以本题的答案是D项senses,因为feelings , touches和tastes都与smells无关。
本句的中心词是复数的sharks , another所修饰的名词一般是单数,所以不会是答案。these和those是表特指的代词,指代前面出现过的名词。由于前面没有先行词,所以也不可能是答案。剩下的other是答案,any other sharks的说法也合乎英语的用法。所以答案为D。
从上下文判断,医学研究人员想要更多了解的是“身体抗病system(系统)”,不会是“身体抗病idea(思想)”、“身体杭病工作(work)”或“身体杭病circle(周期)”。所以答案为A。
本段最后一句意为:医学研究人员研究置鱼的目的是为了找到一种人类抗病的方法。所以空格13所在句子的意思应该是recover (quickly from injuries)。科学家想要探究的应该是有关受伤鲨鱼recover quickly from injuries的原因,而reform“改造”' return“回归”和rely“依靠”只是与答案recover词形上有点相似而已,其意思与上下文的意思风马牛不相及。所以答案为A。
从上下文判断,置鱼的存在能使oceans得益。置鱼不生活在rivers、 forests 或mountains中,所以这三个选项不合适。因此答案为B。
本段的其余三句都是说明为什么置鱼有益于海洋。它们吃海洋动物,结果使得海洋中的动物数量不会过多。weak、 little、 few都与上面表达的意思相反,所以只有D项 great是答案。