A Biological Clock
Every living thing has what scientists call a biological clock that controls behavior. The biological clock tells _____1___ when to form flowers and when the flowers should open1. It tells _____2____ when to leave the protective cocoon茧 and fly away, and it tells animals and human beings when to eat, sleep and wake.
Events outside the plant and animal _____3_____ the actions of some biological clocks. Scientists recently found, for example, that a tiny animal changes the color of its fur ____4_____ the number of hours of daylight. In the short ____5___ of winter, its fur becomes white. The fur becomes gray brown in color in the longer hours of daylight 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 _____6____ twice each year. Birds _____7_____ flying become restless when it is time for the trip, ____8___ they become calm again when the time of the flight has ended.
Scientists say they are beginning to learn which ____9____ of the brain contain biological clocks. An American researcher, Martin Moorhead, said a small group of cells near the front of the brain ____10____ to control the timing of some of our actions. These ____11____ tell a person when to _____12_____, 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 _____13____ our biological clocks affect the way we do our work2. For example, most of us have great difficulty if we must often change to different work hours. _____14____ can take3 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 ____15____ understanding could cut sickness and accidents at work and would help increase a factorys production.
1. A) scientists B) humans C) plants D) animals
2. A) insects B) birds C) fish D) snakes
3. A) effect , 达到 B) affect 影响 C) effected D) affected
4. A) because B) for the reason that C) because of D) since
5. A) months B) days C) minutes D) weeks
6. A) flight B) fly C) movement D) transportation
7. A) prevented from阻止, 妨碍 B) ordered by C) helped by D) intruded on
8. A) and B) but C) therefore D) however
9. A) portions B) parts C) sections D) kinds
10. A) try B) tries C) seem D) seems
11. A) things B) parts C) cells D) actions
12. A) awaken B) wake C) awakening D) wake-up
13. A) how B) why C) where D) what
14. A) We B) It C) They D) You
15. A) so B) with C) such D) if
Public image refers to how a company is viewed by is customers, suppliers, and stockholders, by the financial community, by the communities in which it operates, and by federal and local governments....（查看全文）
The price of hotels in Britain is going up1at any time since the war.There are a humber of rea-sons for this but the2all is the Governmentg economic policy.Manages in factories see3so they are attrac...（查看全文）
阅读一篇短文，文中有15处空白，每个空白处给出了四个选项。应试者根据短文的内容从四个选项中选择一个最佳答案。 Hello，Jill.How nice to see you here，said Jack，l here often?Not as much as Ia like.1 0f.te...（查看全文）
The Bermuda Triangle is one__1__the greatest mysteries of the sea.In this triangular area between Florida，Puerto Rico and Bermuda in Atlantic，ships and airplanes __2__to disappear more often than i...（查看全文）
Cia Andina do Triconos , a Bolivian joint venture of the U.S. Dresser Industries and local investors, which and based its investment __________ an allocation under the metalworking program, closed it...（查看全文）