2018年职称英语综合类考试C级完形填空练习题（3）|职称英语C级
A Special Clock
Every living thing has what scientists call a biological clock that controls behavior.The biological 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.An American 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 clock cells that __________（65） other body activities.
51 A says B asks C talks D tells
52 A reach B leave C escape D enter
53 A affect B adopt C avoid D express
54 A time B value C amount D number
55 A days B months C minutes D weeks
56 A shape B type C form D color
57 A physical B biological C mental D portable
58 A operation B flight C movement D transportation
59 A derived B prevented C originated D protected
60 A but B unless C therefore D if
61 A parts B ideas C sorts D images
62 A tries B likes C seems D wants
63 A functions B places C actions D cells
64 A lie B sleep C stand D walk
65 A build B demand C reflect D control
答案：51.D 52.B 53.A 54.D 55.A 56.D 57.B 58.B 59.B 60.A 61.A 62.C 63.D 64.B 65.D