We have known for a long time that flowe

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问题:

We have known for a long time that flowers of different plants open and close at different times of day. This is so    1   that there seems to be no need to ask the reason for it. Yet no one    2   understands why flowers open and close like this at particular times. The process is not as    3   as we might think, as recent experiments have shown. In one study, flowers were kept in constant    4  . We might expect that the flowers, without any information about the time of day, did not open as they    5   do. As a matter of fact, they    6   to open at their usual time. This suggests that they have some mysterious(神秘的) way of knowing the    7  . Their sense of time does not    8   information from the outside world; it is, so to speak, inside them, a kind of “inner clock”.
This    9   may not seem to be very important. However, it was later found that not just plants but also    10  , including man, have this “inner clock” which    11   the working of their bodies and influences their activities. Men, then, are also influenced by this mysterious    12  . Whether we wish it or not, it affects such things in our life as our need for sleep, our need for food.
In the past, this did not really    13   because people lived in natural condition. In the    14   world, things are different; now there are spacemen, airplane pilots and, in ordinary life, a lot of people who have to work at night. It would be very   15 , then, to know more about the “inner clock”. Such things as flowers might help us understand more about ourselves.
小题1:
A.familiarB.strangeC.similarD.special
小题2:
A.partlyB.personallyC.reallyD.willingly
小题3:
A.complexB.simpleC.matureD.meaningful
小题4:
A.quietnessB.darknessC.lonelinessD.sadness
小题5:
A.finallyB.completelyC.physicallyD.normally
小题6:
A.refusedB.decidedC.continuedD.failed
小题7:
A.timeB.secretC.processD.study
小题8:
A.deal withB.add toC.give awayD.depend on
小题9:
A.discoveryB.activityC.inventionD.method
小题10:
A.beastsB.animalsC.strangersD.humans
小题11:
A.controlsB.studiesC.measuresD.destroys
小题12:
A.worldB.flowerC.powerD.experiment
小题13:
A.happenB.existC.matterD.work
小题14:
A.ancientB.modernC.wonderfulD.peaceful
小题15:
A.hardB.expensiveC.convenientD.important
考点:科教类阅读健康环保类阅读
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为了迎接2010年10月1日国庆节,某城市为举办的大型庆典活动准备了四种保证安全的方案,列表如下:
方案ABCD
经费300万元400万元500万元600万元
安全系数0.60.70.80.9
其中安全系数表示实施此方案能保证安全的系数,每种方案相互独立,每种方案既可独立用,又可以与其它方案合用,合用时,至少有一种方案就能保证整个活动的安全
(I)求A、B两种方案合用,能保证安全的概率;
(II)若总经费在1200万元内(含1200万元),如何组合实施方案可以使安全系数最高?
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制备一张良好的血涂片应除外以下特点()

A.厚薄适宜

B.头体尾分明

C.细胞分布均匀

D.血膜边缘整齐、并留有一定的空隙

E.越厚越好

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直流电动机的转矩与()。

A.电枢电流成正比

B.磁极磁通成正比

C.电枢电流和磁极磁通的乘积成正比

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低压流控法

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激光切割机工工作时不穿齐全工服、工鞋会导致什么后果?

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