We had known for along time that flowers of different plants open and close at different time of day. Yet no one really understands why flowers open and close like this at special time. The question is not as simple as we might think, as recent experiments have shown. In one experiment, flowers were kept in constant (持续的）darkness. We might expect that the flowers ,without any information about the time of the day, did not open as they usually do. In fact, they continue to open at their usual time. This shows that they have some special ways of knowing the time. Their sense(感觉) time does not depend on information from the outside world. It is inside them: a kind of "inner (内部的）clock". This discovery may not seem to be very important. However, it is later found that not just plants but animals have this "inner clock" which control（控制）the working of their bodies and influences their activities. Human beings, then, are also influenced by it. Whether we wish or not, itaffectssuch things in our life as our need for sleep or need for food.
Before the experiment arrived at a conclusion, people had thought that the flowers would____.

A．never open in constant darkness

B．change their usual time to open

C．open ahead of the time as they usually did

D．continue to open at usual time

The sense of time that flowers have is connected with_____________.

A．its age and size

B．light and temperature

C．a kind of strange power(力量）inside them

D．some unknown information from the outside world

What will happen if we make good use of the "inner clock"

A．We'll need less sleep or food.

B．We'll be able to sleep as long as we wish to.

C．We'll be able to change our work time when necessary.

D．We'll have more energy to do our work better.

What's the Chinese meaning of the underlined word" affects"

A．产生

B．影响

C．给予

D．依赖

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