Passage 19

　　Three men traveling on a train began a conversation about the world's greatest wonders.

　　“In my opinion,” the first man said, “the Egyptian pyramids are the world's greatest wonder. Although they were built thousands of years ago, they are still standing. And remember: the people who built them had only simple tools. They did not have the kind of machinery that builders and engineers have today.”

　　“I agree that the pyramids in Egypt are wonderful,” the second man said, “but I do not think they are the greatest wonder. I believe computers are more wonderful than the pyramids. They have taken people to the moon and brought them back safely. In seconds，they carry out mathematical calculations that would take a person a hundred years to do.”

　　He turned to the third man and asked, “What do you think is the greatest wonder in the world？”

　　The third man thought for a long time，and then he said, “Well，I agree that the pyramids are wonderful, and I agree that computers are wonderful, too. However，in my opinion, the most wonderful thing in the world is this thermos.”

　　And he took a thermos out of his bag and held it up.