2. 外语
  3. Every living thing has what scientists call a biological clock that controls behavior. It tells plants when to【C1】______flowers

Every living thing has what scientists call a biological clock that controls behavior. It tells plants when to【C1】______flowers

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问题     Every living thing has what scientists call a biological clock that controls behavior. It tells plants when to【C1】______flowers and insects when to leave the protective cocoon(茧)and fly away. And it tells animals and human beings when to【C2】______, sleep and seek food. It controls our body temperatures, the【C3】______of some hormones and even dreams.
    Events【C4】______the plant and animal affect its actions. Scientists recently found that a tiny animal called Siberain hamster changes the color of its【C5】______because of the number of hours of【C6】______. In shorter days of winter its fur becomes white. The fur becomes gray-brown in longer【C7】______of daylight summer.
   【C8】______signals control other biological clocks. German scientists found that some internal one seems to order birds to begin their【C9】______flights two times each year. Birds prevented from flying become【C10】______when it is time for the trip. 【C11】______they become calm again when the time of the flight has ended. A mix of outside and internal events controls some biological clocks; such things as heartbeat and the daily change from sleep to walking take place because of both external and internal signals.
    Scientists are beginning to learn【C12】______parts of the brain contain biological clocks. A researcher at Harvard University, Dr. Martin Moore Ede, said a small group of cells near the front of the brain seemed to control the【C13】______of some of our actions. Probably there are other cells to control other body activities. He is studying【C14】______they affect the way we do our work. Most of us have great difficulty if we【C15】______often change to different work hours. It can【C16】______many days for a human body to【C17】______the major change in work hours. Industrial officials should have a better【C18】______of biological clocks and how they affect workers. He said such an understanding could【C19】______sickness and accidents at work, and would help increase【C20】______.
【C4】
选项 A、outside
B、aside
C、inside
D、beside
答案A
解析 语义衔接题。本空所在句是第二段的主题句。由本段所举的西伯利亚仓鼠根据日照的时间改变皮毛颜色的例子可推断，本段说的是动植物外部的因素也可能影响生物钟，[A]outside意为“在…之外”，符合语义，故答案为[A]。
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