阅读理解。 One day an old woman was traveling alone in the mountains. Suddenly she saw something shining in the stream. When she came close, she found it was a precious stone. She put the stone into her bag and went on with her trip. The next day the old woman met a young man, who was also a traveler in the mountains. The young man looked very hungry, so the old woman opened her bag to share her food. The hungry traveler saw the precious stone and asked carefully, 'The stone is beautiful. Would you like to give it to me?' 'Sure. Why not?' the woman said, and handed the stone to him. The young man left happily with the stone. He knew it was worth enough to give him security for a lifetime. But a few days later he came back to return the stone to the woman. 'I've been thinking,' he said. 'I know how valuable the stone is, but I give it back and hope that you can give me something even more precious. Give me what you have within your bag.' The woman opened her bag. It was almost empty. She looked at the young man and smiled, 'I have nothing special in my bag, but I do have something precious-the joy of giving!' The young man felt ashamed and left silently. 1. How did the young man find the precious stone? [     ] A. He found it in his food. B. He dug it out in a valley. C. He saw it in the woman's bag. D. He noticed it shining in the stream. 2. What does the underlined word 'security' in Paragraph 4 probably mean? [     ] A. Money. B. Worry. C. Health. D. Trouble. 3. The man returned the stone to the woman because _____. [     ] A. he found the stone was not precious B. he understood the real meaning of joy C. he felt embarrassed at taking away the stone D. he wanted to get something even more precious 4. Which of the following would be the best title of the passage? [     ] A. A special stone B. The joy of giving C. A woman and a young man D. An experience in the mountains