【单选题】
阅读下面的短文，文中有15处空白，每处空白给出了4个选项，请根据短文的内容从 4个选项中选择1个最佳答案。
Every living thing has what scientists call a biological clock that controls behavior. The biologicai clock______(51) plants when to form flowers and when the flowers should open. It tells insects when to______(52) the protective cocoon (防护卵袋) and fly away, and it tells animals and human beings when to eat, sleep and wake.
Events outside the plant and animal______(53) the actions of some biological clocks. Scientists recently found, for example, that a tiny animal changes the color of its fur because of the______(54) of hours of daylight. In the short______(55) of winter, its fur becomes white. The fur becomes gray brown in______(56) in the longer hours of daylight in summer.
Inner signals control other______(57) clocks. German scientists found that some kind of internal clock seems’ to order birds to begin their long migration ______(58) twice each year.Birds______(59) from flying become restless when it is time for the trip,______(60) they become calm again when the time of the flight has endeD、
Scientists say they are beginning to learn which______(61) of the brain contain biological clocks.AnAmerican researcher, Martin Moorhead, said a small group of cells near the front of the brain______(62) to control the timing of some of our actions. These______(63) tell a person when to wake, when to______(64) and when to seek fooD、Scientists say there probably are other biological clockCells that ______(65) other body activities.
B．asks
C．tells
D．talks
网考网参考答案：C
网考网解析：
暂无解析 document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>
发布评论 查看全部评论