阅读短文，从每小题所给的A、B、C三个选项中选出最佳选项．

Whenever the sun dropped and the blue sky came up，my father and I used to climb the mountain near my house．Walking together，my father and I used to have a lot of conversations through which I learned lessons from his experiences．He always told me，"You should have goals like climbing the mountain．"Without the mountain﹣climbing that we both enjoyed，we couldn't have enough time to spend together because my father was very busy．I really got a lot from the mountain﹣climbing．It gave me time to talk with my father and to be in deep thought as well as develop my patience（耐力）．

Once we climbed a very high mountain．It was so challenging（挑战性的） for me because I was only ten years old．During the first few hours of climbing，I enjoyed the flowers and trees，and the birds' singing．But as time passed，I got a pain in both of my legs．I wanted to quit climbing，In fact，I hated it at that moment，but my father said to me，"You can always see a beautiful sky at the top of the mountain，but you can't see it before you reach the top．Only there at the top，can you see all of the nice things，which is just like your life．"

At that time，I was too young to understand his words．But later after that，I got new hope and confidence．I found myself standing at the top of the sky，which was as clear as crystal（水晶）．

51．Why couldn't the writer and his father have enough time to spend together？　　

A．Because the writer was very busy．

B．Because the writer's father was very busy．

C．Because they didn't live together．

52．The passage tells us that mountain﹣climbing was　　 for father and son．

A．enjoyable           B．hard          C．terrible

53．Which of the following is similar in meaning to the father's words in the second paragraph？　　

A．You will get all you need at the top of the mountain．

B．The sky is always as clear as crystal．

C．Never give up halfway．

54．The word"quit"in the passage means"　　"in Chinese．

A．继续             B．推迟              C．停止

55．We can learn from the last paragraph that　　．

A．the writer was very successful in his life

B．the writer didn't reach the top of the mountain

C．though the writer was young，he could understand his father．