阅读理解
One day, at night, a thief tried crawling (爬行) into a farmer couple's house. In the house lived many mice. The woman in the moonlight saw a mouse crawl into the house. “Look! In comes one.” She said to the man in the house. The thief was so frightened that he hurriedly crawled out of the house and said to the one waiting outside, “She found me when I was just in.” But the thief outside didn't believe him, so he said, “Let us two try to crawl into the house together.” At that time two mice happened to crawl into the house, too. The woman saw the mice and shouted, “In come two, catch them!” The two thieves were terribly frightened. The man in the house said, “You saw them come in but where are they? I will catch them tonight” The two thieves started running away at once.
The two thieves wanted to make it clear whether they had been found or not the night before. The next day they acted as men selling sweet potatoes and came before the house. The man and the woman were working in their fields. The rein (缰绳) broke and the woman came home for a new one. She saw two men selling sweet potatoes and wanted to buy some. She picked out two which looked like mice. At the time the man couldn't wait for her any longer in the fields and he ran back from the fields to hurry her up. The woman showed the sweet potatoes to the man and said, “How they look like the two of last night!” The man said, “I asked you to fetch a rein, why don't you hurry for it?” The two thieves ran away quickly without their sweet potatoes.
（其中R是烃基）