阅读短文,选择最佳答案。
This is a story about a schoolboy, Bill. One day his mother told him to post a letter. Bill walked down the street. He didn't see a letter box in the street, but he saw a basket with a sign on it. The sign said, PUT LITTER IN THIIS BASKET." I can read," said Bill," But they didn't write the word right."
Bill put the letter in the basket. Then he ran home to tell his mother about the basket. "Oh. child," said his mother, "You put the letter in a litter basket. A litter basket is for old paper and other things that are not good."
"Oh, is that so?" said Bill. "Yes, it is. The word is LITTER, not LETTER. Now go and get the letter quickly and post it." said his mother.