2. 职称英语
  3. The term biological clock is applied to the means by which living things adj

The term biological clock is applied to the means by which living things adj

游客2023-07-03  49
问题     The term biological clock is applied to the means by which living things adjust their activity patterns, without any【B1】______ cue, to the time of day, or the month, or the year. The biological clocks seem to be beautifully【B2】______ the needs of living things. They are affected but little, if at all, by drugs, chemicals, or wide temperature difference —【B3】______ which may alter substantially the rates of all ordinary processes of the body.
    The nature of the biological clocks’【B4】______ is still a mystery. Two quite different theories can【B5】______ them. According to the first of these theories, each individual contains its own independent timing system. This is believed to have【B6】______, aided by natural selection, as an adaptation to the rhythmic environment. It has now become independent of the environment. The other theory holds that living things react【B7】______ to their rhythmic physical environment. The setting of their biological clocks, therefore,【B8】______ a constant adjustment to subtle environment forces. But the search for the【B9】______ timing system has been futile thus far. Not only has no independent timing system ever been discovered, but there has not yet been even a guess【B10】______ its nature. [br] 【B6】
选项
答案 evolved
解析 此空需要动词的过去分词，与空格前的have构成完成时态作谓语。evolve“进化，发展”，其过去分词在词尾加-d。
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