题目内容：
根据下面资料，回答题 When did you last see a polar bear? On a trip to a zoo, perhaps? If you had attended a winteractivity in New York a few years ago ,you would have seen a whole polar bear club．These "Polar Bears"
are people who meet frequently in winter to swim in freezing cold water．That day, the air temperature was3 ℃, and the water temperature was a bit higher．The members of the Polar Bear Club at Coney Island,New York are usually about the age of 60．Members must satisfy two requirements．First, they must getalong well with everyone else in the group．This is very important because there are so many different
kinds of people in the club．Polar Bears must also agree to swim outdoors at least twice a month fromNovember through February．
Doctors do not agree about the medical effects of cold-water swimming．Some are worried about thedangers of a condition in which the body' s temperature drops so low that finally the heart stops．Otherdoctors, however, point out that there is more danger of a heart attack during summer swimming because thedifference between the air temperature and water temperature is much greater in summer than in winter．
The Polar Bears themselves are satisfied with the benefits (or advantages) of cold-water swimming．
They say that their favorite form of exercise is very good for the circulatory system(循环系统) because itforces the blood to move fast to keep the body warm．Cold-water swimmers usually turn bright red after afew minutes in the water．A person who turns blue probably has a very poor circulatory system and shouldnot try cold-water swimming．
The main benefits (or advantages) of cold-water swimming are probably mental．The Polar Bearslove to swim year-round；they find it fun and relaxing．As one 70-year-old woman says, " When I go intothe water, I pour my troubles into the ocean and let them float away．"
Doctors_______． A．encourage people to take part in cold-water swimming actively
A．encourage people to take part in cold-water swimming actively
B．point out the possible danger of blood illness during cold-water swimming
B．point out the possible danger of blood illness during cold-water swimming
C．believe swimming is helpful both in winter and in summer
C．believe swimming is helpful both in winter and in summer
D．have different ideas about the medical effects of cold-water swimming
D．have different ideas about the medical effects of cold-water swimming
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