题目内容：

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 all kinds of tricks(把戏).

George had a friend. His name was Mark. One day George offered to take Mark up in his plane.

Mark thought, "I travelled in a big plane several times, but I never travel in a small one, so I'll go."

They went up and George did all kinds of tricks in the air. When they came down again, Mark

was very glad to be back safely, and he said to his friend in a shaking 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 trip in your small plane," answered Mark, "I'll never take it anymore."

1.Did Mark travel in a big plane in the past?

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2.When did George buy a small plane?

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3.What did George make his plane do?

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4.In fact, how many trips did Mark take in the small plane?

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