When George was thirty-five, he bought a small plane and learned to fly it. He soon became very good at it and made his plane do ①all kinds of tricks.

    George had a friend. His name was Mark. One day George wanted to take Mark up in his plane. Mark thought, "I've traveled in a big plane several times, but I've never been in a small one. So I'll do."

    They went up, and George flew around for half an hour and did all kind sof tricks in the air.

    When they came down again, Mark was very glad to be back ②safely, and he said to his friend in a shaking (颤抖的)voice ,"Well ,George, thank you very much for those two trips in your plane."

    George was very surprised and said, "Two trips?"

    "Yes, my first and my last," answered Mark.