阅读下面短文，从所给A、B、C、D四个选项中选出最佳答案．

One day a man was walking through a big city．On a street corner he saw a boy with a number of small birds for sale，in a cage．

He looked with sadness upon the little prisonersflying about the cage，jumping up and down，beating their wings，and trying to get out．

He stood for some time looking at the birds．At last he said to the boy，"How much do you ask for your birds？"

"Fifty cents a piece，sir，"said the boy．"I do not mean how much a piece．"said the man，"but how much for all of them？I want to buy them all"

The boy began to count．and found they came to five dollars．"There is your money，"said the man．The boy took it，well pleased with his morning's trade．

After giving the money，the man opened the cage door，and let all the birds fly away．

The boy，in great surprise，cried，"What did you do that for，sir？You have lost all your birds"

"I will tell you why I did it，"said the man．"I was shut up three years in a French prison（监狱） prisoner of war，and I am molved （下定决心）never to see anything in prison which I can make free．"

36．What did the boy do that day？ 　　

A．	Selling some birds．
B．	Flying some birds．
C．	Beating some birds．
D．	Buying some birds．

37．The underlined word"prisoners"probably means 　　

A．	嫌疑犯
B．	战争犯
C．	笼中鸟
D．	流浪者

38．How many birds did the man buy？ 　　

A．	5
B．	10
C．	15
D．	50

39．When did the story happen？ 　　

A．	At noon．
B．	In the morning．
C．	In the afternoon
D．	In the evening．

40．Why did the man let the birds fly away？ 　　

A．	He didn'like the birds．
B．	He loved the birds very much．
C．	He wanted to protect the environment．
D．	He wanted to see anything in prison get free．