A Biological Clock: Z$ Y* i3 I6 q8 M5 b( d
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 open. It tells __2__ when to leave the protective cocoon and fly away, and it tells animals and human beings when to eat, sleep and wake.
- ^- Q" j2 b- N( n* ]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 in summer.6 T- s8 x# _! E5 Z5 m( l0 \
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__ from flying become restless when it is time for the trip, __8__ they become calm again when the time of the flight has ended.# ^6 r" o; P p% y5 v1 I6 J
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.4 Y/ T A( C+ Q
Dr. Moorhead is studying __13__ our biological clocks affect the way we do our work. For example, most of us have great difficulty if we must often change to different work hours. __14__ can take 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 factory's production.
' r7 I) I; y9 ^1. A) scientists B) humans C) plants D) animals& f8 A1 f2 ^/ f0 [! \
2. A) insects B) birds C) fish D) snakes% c+ m7 l8 R# \* h1 p D6 S
3. A) effect B) affect C) effected D) affected1 O& N F, g. }/ t+ y
4. A) because B) for the reason that C) because of D) since% h! J% V# s; v. P: g
5. A) months B) days C) minutes D) weeks+ I6 f& D m3 I* l. A
6. A) flight B) fly C) movement D) transportation
, d: d8 x# T8 Y& B7. A) prevented from B) ordered by C) helped by D) intruded on/ J/ v% o5 f. v9 U5 G1 b& }8 m: y
8. A) and B) but C) therefore D) however
( l$ j0 F/ v: {* e' g5 O9. A) portions B) parts C) sections D kinds8 {( \9 h( ~2 ~% i- W
10. A) try B) tries C) seem D) seems
. f, l" V6 t1 N) C5 p, I11. A) things B) parts C) cells D) actions+ i; m( \5 A3 q
12. A) awaken B) wake C) awake D) wake-up! j0 W4 D6 j4 `% Q* |( ~9 F, ^
13. A) how B) why C) where D) what" i6 D9 K1 k- [- ^5 O( d9 H
14. A) We B) It C) They D) You/ [+ g f& o$ [2 k) j
15. A) so B) with C) such D) if
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发表于 2012-8-15 23:30:26
