用所给动词的适当形式填空。

       Michael and Derek arc good friends, but they like to pull each other's leg sometimes. One day during

  the holidays they decided   1_  (go) to London together. They went to the station and bought their tickets.

   When the train came in, Michael boarded it first and without    2   (know) it, dropped his ticket on the

  platform as he got into the carriage. Derek, who was close behind, saw the ticket fall and quickly picked

  it up. Without a word to his friend, he put it in his pocket. After they had been in the train a little while,

  they heard the ticket inspector coming down the corridor, shouting, "Ticket, please!" Michael looked for

  his and of course   3   (not find) it. "Oh dear, I can't find my ticket, Derek," he said. "  4   (have) another

  look, Michael; it must be somewhere," said Derek. "No, I can't find it anywhere. Whatever shall I do?  

  Perhaps you had better hide under the seat; then the inspector   5   (not know) you are here." So Michael

   crawled under the seat as far as he could and lay perfectly still. Presently the door opened, and the

  inspector came in. "Ticket, please," he said. Derek handed him two tickets, and said, "This is mine. The

  other belongs to my friend who prefers to travel under the seat. "

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