题目内容：
根据以下材料回答第题：I can clearly remember the first time I met Mr. Andrews, my old headmaster,（21）that was over twenty years ago . During the war ,I was at school in the north of England . As soon as it ended, my family returned to London. There were not enough schools left for children to go to and my father had to go from one school to another, asking them to（22） me as a pupil . I used to go with him but he had such a （23）time trying to persuade people even to see him that I seldom had to do any tests. We had been to all the schools near where we lived ,but the more（24）my father argued ,the more it became. In the end ,we went to a school about five miles away from home. The headmaster kept us waiting for （25）an hour. While we were waiting , I （26）around at the school building ,which was one of those old Victorian structures, completely out of date but still standing. I could hear the boys playing in the playground outside when the headmaster’s secretary finally （27）us into his office. Mr. Andrews spoke to me first ,“Why do you want to come here ?” he asked. I had been thinking of saying something about studying but couldn’t （28）remembering the boys outside .“I don’t know anyone in London, ” I said . “I like to play with the other boys. I like to read a lot of books too,” I （29）. “All right ,”Mr. Andrews said . “We have one place（30）,in face.”My two years at that school were among the happiest of my life.填入（21）处的最佳答案是（）。 A．if
B．despite
C．although
D．since
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