Martin is an American boy. He is eight years old. His parents   41  _ five years ago and he is now living with his grandmother in New York.
　　One morning,  Jimmy ,  one of his classmates, came to his home with an exercises book in his hand. Jimmy lives in a house not far from Martin's. They often go to school together.
　　"Would you help me with this maths problem?" Jimmy said as soon as he came into the room. "It's too hard for me and I can't work it out."
　　"Let me try, " Martin said. "I   42  it isn't too hard for me. "
　　Martin tried his best but he couldn't work it out,   43   .
　　"If we had a small computer,  all the problems would be  44   for us to do. " Jimmy said.
　　"A small computer . . . , " Martin thought for a minute,  then he said, "I've got an idea. We can   45  one in a shop. "
　　"A computer is very   46   ,  and we don’t have enough money. "
　　"That's OK, " said Martin. "We can ask the new president (总统)   47  some money. He said he would help anyone in trouble. I' m sure he will help us. He is very rich, you know."
　　So they decided to write a letter to the new president. Soon the letter was finished and they hurried to the post office.
　　In front of the post office stood a small box. They   48   the letter into the box carefully and went home happily.
The next morning, they    49   the post office on their way to school. They found   50  ,  the box was not a post box but trash-box (果皮箱).