完形填空
       Once upon a time there was a little orphan（孤儿） who always wished that he could fly like a bird. It was very   1   for him to understand why he could not fly.
　　There was another little boy who was crippled（瘸子）. One day the orphan came to a park, where he saw the little crippled boy   2   in the sand alone.
　　He ran over to the little crippled boy and asked him if he had ever wanted to fly like a bird.
　　“No, ” he said. “  3  I've been thinking about what it would be like to walk and run like   4  .”
　　“That is very sad, ” said the little orphan. “Do you think we could be friends?”
　　“Sure, ”said the little crippled boy.
　　The two little boys played for hours.  5 of them felt as lonely as they have been before. Then the little crippled   6 father came with a wheelchair to  7  his son. The little orphan ran over to him and said something into his ear.
　　“That would be Okay, ”said the man.
　　The little orphan ran back to his friend and said, "You are my only friend and I   8 I could do something to make you walk and run like others. 9  , I can't. But there is something that I can do for you."
　　The little orphan boy turned10  and told his friend to slide onto his back. Then he began to run across the grass. He ran faster and faster,  11 the little crippled boy on his back.
The father began to cry with tears as his son shouted at the top of his   12 , "I am FLYING! Daddy, I am FLYING!"
That's the little orphan who helped the crippled boy  13 the dream to fly in his life and moved the father.14 he didn't know the reason why he could not fly, he helped another boy fly and harvested happiness from it. Let's always be ready to help others because helping others is helping   15 .