阅读理解。        We have known for a long time that flowers of different plants open

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阅读理解。        We have known for a long time that flowers of different plants open and close at different time of day.
This is so familiar that there seems to be no need to ask the reason for it. Yet no one really understands why
flowers open and close like this at particular times. The process (过程) is not as simple as we might think, as
recent experiments have shown. In one study, flowers were kept in constant (连续的) darkness. We might
expect that the flowers, without any information about the time of day, did not open as they normally do. In
fact, they continued to open at their usual time. This suggests that they have some mysterious (神秘的) way
of knowing the time. Their sense of time does not depend on information from the outside world; it is, so to
speak, inside them, a kind of "inner clock".
         This discovery (发现) may not seem to be very important. However, it was later found that not just
plants but also animals -including man -have this "inner clock" which controls the working of their bodies and
influences (影响) their activities. Men, then, are also influenced by this mysterious power. 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 matter very much because people lived in natural condition. In the modern
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 useful, then, to know more about the "inner clock". Such ordinary
things as flowers might help us understand more about ourselves.

答案

1-5: B D A C A