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.

46. A recent experiment showed that ________________.  

A. different flowers open and close at different times of day  

B. for their opening and closing, flowers do not need information from the outside world  

C. flowers are influenced by weak light even when they are in a dark room  

D. flowers can be used for telling the time

47. Further study of the “inner clock” will be useful because ______________.   

A. it might help us in some way   

B. we do not yet understand plants and animals well enough   

C. the number of spacemen and airplane pilots is fast increasing   

D. we should try to live more naturally than we do now

48. The “inner clock” _________________________.   

A. is an unimportant discovery           B. is only found in animals   

C. has not been understood by far         D. has an effect on human life

49. Kept in constant darkness, flowers ________________________.   

A. will not open or close as usual           

B. will not open any longer   

C. will open as they do in natural conditions  

D. will always remain in full blossom (开花)

50. ____________ have a mysterious power of knowing time without information from the outside world.   

A. Animals including man as well as plants     

B. All living things except man   

C. Flowers are the only things in the world that    

D. Neither animals nor plants

As a young boy my family was very poor. I would often help do something for the neighbors to  36  a little pocket money.

One day I  37  on the door of an elderly woman and asked  38  she needed me to clean the yard. She asked why I was not in  39  and I showed her my worn  40 , which no longer kept me warm. She  41  me to work in the yard. When I finished, she looked at me and said, “I suppose you want to be  42  now.” She then  43  a jar filled with dollar bills and said, “I’m glad you’ve done a  44  job today but that is not something you should be doing again. I want you to  45  new clothes and get back to school. I also want you to come back to  46  me with your report card and I will  47  you when I see you have worked hard and have some good  48 . Now reach out your little hands and take out as much  49  as you can.”

I put my hands in the jar and  50  so much money that it was  51  for me to buy what I badly needed. Later, I returned several times to see the woman and she did just as she  52 . She looked at my report card and gave me a handful of dollars and some delicious food every time I  53  her that I had an “A”.

I was twelve years old when I moved from that neighborhood. I will never forget the huge  54 this wonderful lady made over my life with her  55 . This is something I hope to do myself in this lifetime over and over again.