A Biological Clock
Every living thing has what scientists call a biological clock that controls behavior. The biological clock tells ___C__1___ when to form flowers and when the flowers should open1. It tells ___A__2____ when to leave the protective cocoon and fly away, and it tells animals and human beings when to eat, sleep and wake.
Events outside the plant and animal ___B__3_____ the actions of some biological clocks. Scientists recently found, for example, that a tiny animal changes the color of its fur __C__4_____ the number of hours of daylight. In the short ____5__B_ 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 ___A__6____ twice each year. Birds ____A_7_____ flying become restless when it is time for the trip, _B___8___ they become calm again when the time of the flight has ended.
Scientists say they are beginning to learn which __B__9____ of the brain contain biological clocks. An American researcher, Martin Moorhead, said a small group of cells near the front of the brain __D__10____ to control the timing of some of our actions. These ___C_11____ tell a person when to ___A__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 __A___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. ___B__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 __C__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 B) affect 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 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
英语写作中如何表示变化
表示原因的英语句式
英语几个典型的句型
接不定式作宾补的36个常用动词
片语连接词
表示措施的英语句子
如何推销自己
英语美文:老朋友
如何阐述结论
我相信我的梦想
提出自己看法的典型例句
关于假资讯之“成都小伙迎娶土耳其美女”的情景会话
十二生肖相关习语
OTT是什么?
理想照进现实
英语写作如何表示数量
大自然是我们的母亲
英语国家生存英语精选
撒切尔夫人的名人格言
常见的英语口语
母爱
接不定式作宾语的英语动词短语
五条英语语法必须掌握的规则
该如何给外国人指路
H7N9型禽流感相关英语单词
朝鲜或进行导弹测试
but的不同用法
有关撒切尔夫人的名言
副词的用法
伊朗遭遇80多次余震
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |