阅读下面短文,掌握其大意,然后从各题所给的四个选项（A、B、C、D）中，选出最佳选项。

　　Before the 1950s,running the mile in under four minutes was considered impossible．Gradually though,times for the mile run did 　　1　　．By the early 1950s,it looked as though a four minute mile was indeed 　　2　　．

　　A British 　　3　　,Roger Bannister,decided to try to break the four minute barrier．The decision to work for this 　　4　　 meant hours of painful,boring preparation ahead of him,but to Bannister,the goal was well worth the 　　5　　．In December,1953,his 　　6　　 began．It included a series of ten quarter-mile sprints（全速跑）,to be done in sixty seconds each．He 　　7　　 himself a two-minute rest after each quartermile．By early February of 1954,he had gotten his time down to 　　8　　 seconds;this meant a 4∶04 mile．Here Roger reached a plateau（停滞）．He couldn't 　　9　　 to get his time for the quarter-mile down to 60 seconds．　　10　　,he and a friend took time away from training to go mountain climbing in Scotland for three days．This 　　11　　 was conside quite reckless（轻率的）,since a sprained ankle（扭伤踝骨）could 　　12　　 him weeks of valuable training．However,the mountain climbing 　　13　　 gave him the mental advantage he needed．When he 　　14　　 training,he ran the ten guarter-miles again;his time was down to 59 seconds for each quarter mile sprint．

　　When 　　15　　 day arrived,strong winds were blowing and running conditions were poor．What a 　　16　　 decision！Should he run,going for he 　　17　　?Or,should he wait for the next race,days later,hoping for the 　　18　　 to improve?If he did wait,he risked losing his peak physical and mental 　　19　　 Bannister decided to go ahead．It was the 　　20　　 decision．At race time,the wind died somewhat,and Bannister ran effortlessly,the fastest mile in human history in— under four minutes．

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