[解析]
(1)C 细节理解题.根据第一段最后两句Members must satisfy two requirements.First,they must get along well with everyone else in the group.Polar Bears must also agree to swim outdoors at least twice a month from November through February.可知,成员必须具备两个条件:一,能够与别人友好相处;二,从十二月到二月至少每月两次户外游泳.(每月两次即四个月八次).故选C.
(2)D.细节理解题.根据第二段Doctors do not agree about the medical effects of cold﹣water swimming,医生们不同意冷水游泳的医学效果,可知医生对冬泳的影响有不同的意见,故选D.
(3)B.细节理解题.根据第二段第三句Other doctors,however,point out that there is more danger of a heart attack during summer swimming.because the difference between the air temperature and water temperature is much greater in summer than in winter.然而,其他医生指出,在夏季游泳时心脏病发作的危险更大.因为夏季气温和水温的差异比冬季大得多,可知在夏天在冷水中游泳更可能导致心脏病.故B正确.
(4)C.细节理解题.根据第四段第二句The Polar Bears love to swim year﹣round,they find it fun and relaxing."北极熊"一年到头都喜欢游泳,他们觉得游泳很有趣,也很放松.说明这些人喜欢全年都游泳,认为很有趣并让人很轻松.故C正确.
(5)A.主旨大意题.本文主要了Polar Bears,由第一段These"Polar Bears"are people who meet frequently in the winter to swim in freezing cold water."北极熊"是经常在冬天见面,在冰冷的水中游泳的人,可知Polar Bears即是喜欢冬泳的人.故A正确.