完形填空。 Martin is an American boy. He's eight 1 old. One evening, Jimmy, one of his classmates, came to his home with an expensive book in his hand. "Could you help me 2 this maths problem?" Jimmy said as soon as he came into the room. "It's toohard for 3 ." "Let me 4 ," Martin said. "I hope it isn't hard for me." Martin tried his best but he couldn't work it out, either. " 5 we had a small computer, all the problemswould be easy enough for us to do," Jimmy said. "A small computer…" Martin thought for a minute, and then he said, "I've got a(n) 6 . We can buy one in a shop!" "A computer is very 7 , and we don't have enough money." "That's OK," said Martin. "We can ask the new president (总统) for some money. He said he would helpanyone in trouble. I 8 he will help us. He is very 9 , you know." So they 10 to write a letter to the new president. Soon they finished the letter and hurried to the 11 office. In front of the office stood a small box. They 12 the letter into the box 13 and went home happily. The next morning, they passed the post office on their way to school. They found, to their 14 , the box was not a post-box, 15 a trash can (垃圾箱).