题目内容：
根据以下材料回答题 Most people agree that fencing (击剑) is one sport in which a person must be at least 30 years old before he learns all he needs to know about the sport. (1 ) Clark Summers of the University of Detroit (2 ) that this doesn't always have to be (3 ).
Clark is a different kind of fencer in a lot of (4 ). He is American, while most fencers are from the (5) of Europe. He is black while most fencers in the past have been (6 ). And he is 7 ) 22 years old.
Many people (8) that Clark is the most promising fencer in this country today. Although he is young, he has been able to (9) the necessary skills. Already he has won a number of fencing contest (竟赛) (10) older fencers. He is almost (11) to become a member of the U. S. Olympic(奥林匹克 ) fencing team!
"There is no (12) danger in fencing, today, Clark says. "But I never (13) that fencing was not always a sport. In the old days, People fenced to(14)a quarrel. Each match was a matter of (15) If that (16) true in the matches I (17) in today, every touch against me would mean that I (18) wounded or killed. So I try to play （19) l were fencing for my life. I don't like, the idea of being (20) ! "
A．And
B．But
C．Then
D．So
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