A Biological Clock Every living thing has what scientists call a biological clock that controls behavior. The biological clo

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问题                             A Biological Clock
    Every living thing has what scientists call a biological clock that controls behavior. The biological clock tells【C1】______when to form flowers and when the flowers should open. It tells【C2】______when to leave the protective cocoons and fly away, and it tells animals and human beings when to eat, sleep and wake.
    Events outside the plant and animal【C3】______the actions of some biological clocks. Scientists recently found, for example, that a tiny animal changes the color of its fur【C4】______the number of hours of daylight. In the short【C5】______of winter, its fur becomes white. The fur becomes gray brown in color in the longer hours of daylight in summer.
    Inner signals control other biological clocks. German scientists found that some kind of internal clock seems to order birds to begin their long migration【C6】______twice each year. Birds【C7】______flying become restless when it is time for the trip, 【C8】______they become calm again when the time of the flight has ended.
    Scientists say they are beginning to learn which【C9】______of the brain contain biological clocks. An American researcher, Martin Moorhead, said a small group of cells near the front of the brain【C10】______to control the timing of some of our actions. These【C11】______tell a person when to【C12】______, when to sleep and when to seek food. Scientists say there probably are other biological clock cells that control other body activities.
    Dr. Moorhead is studying【C13】______our biological clocks affect the way we do our work. For example, most of us have great difficulty if we must often change to different work hours.
    【C14】______can take many days for a human body to accept the major change in work hours. Dr. Moorhead said industrial officials should have a better understanding of biological clocks and how they affect workers. He said【C15】______understanding could cut sickness and accidents at work and would help increase a factory’s production.
【C9】

选项 A、portions
B、parts
C、sections
D、kinds

答案B

解析 句意:科学家们指出。他们开始探究大脑内部的哪些……存在生物钟。四个选项A项portions“部分”,侧重指从整体中所分配到的那一部分,含一定的独立意义;B项parts“部分”,含义广泛,常指整体中可大可小的一部分,也可指整体中可分开的独立部分;C项sections“部分”,侧重指整体中分区,部分与部分之间有显著界限;D项kinds“种类”。从句意可判断B项符合,故本题选B。
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