George liked flying a plane. Once he bought a small plane and learned how to fly it. He soon became so good that he could make his plane do all kinds of tricks . George had a friend. His name was Peter. One day George said to his friend, " Peter, would you like to have a trip in my plane?" Peter thought, " I've traveled in a big plane several times, but I've never been in a small one, so I'll go." They went up, and George flew around for half an hour and did all kinds of tricks.Peter said in a shaken voice , " Well, George, thank you very much for these two trips in your plane." George was very surprised and asked, " Two trips? " "Yes, my first and my last." Answered Peter. From the passage we know that   _   .
Peter thanked George for the nice trip Peter thought it was wonderful to have such a trip Peter felt surprised that his friend could fly so well Peter was worried about his safety while George was doing tricks in the sky