（一）SharksPerformaServiceforEarth'sWaters.根据材料，回答下列问题。Itishardtogetpeopl

共享题干题                         （一）Sharks Perform a Service for Earth's Waters.根据材料，回答下列问题。    It is hard to get people to think of sharks as anything but a deadly enemy. They are thought to________  (51 )people frequently. But these fish perform a ________ (52 )service for earth's waters and for human beings. Yet business and sport fishing are threatening their________ (53). Some sharks are at________  (54) of disappearing from earth.   Warm weather may influence both fish and shark activity. Many fish swim near coastal areas________  (55 ) their warm waters. Experts say sharks may follow the fish into the same areas,________  (56)people also swim. In fact,most sharks do not purposely charge at or bite humans.   They are thought to mistake a person________  ( 57 ) a 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 es up. Those are the________ (58 )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 water, such as blood, body liquids and________ (59)produced by animals. These powerful________  (60) help sharks find their food. Sharks eat fish, any________  ( 61 ) sharks ,and plants that live in the ocean.  Medical researchers want to learn more about the shark's body defense and immune systems________ .(62) disease. Researchers know that sharks ________  (63)quickly from injuries. They study the shark in hopes of finding a way to fight human disease.Sharks are important for the world's________ .(64). They eat injured and diseased fish. Their hunting activities mean that the numbers of other fish in ocean waters do not bee too________ (65). This protects the plants and other forms of life that exist in the oceans.1.[不定向选择题]________________A.recover B.reform C.return D.rely 2.[不定向选择题]________________A.rivers B.oceans C.forests D.mountions