"tropical of cancer"的cancer是什么意思?

tropical of cancer的cancer是什么意思? 请问为什么北回归线的英文名字叫 tropical of Cancer,而南回归线叫 tropical of Capricorn 依据什么原则而命名的?为什么会用星座来命名呢?而且为何偏用巨蟹座 和 摩羯座来表示? tropical TROPIC OF CANCER怎么样 TROPIC OF CANCER CD怎么样 Cancer the risk of cancer的中文 in crease the risk of cancer WENDEKREIS DES KREBSES TROPIC OF CANCER怎么样 Journal of Cancer 影响因子是多少 you were the cancer of my Half of stomach cancer death in 北回归线的英文为什么叫做Tropic of Cancer?cancer是癌症,和北回归线有什么关系? in 1993,Audrey Hepburn passed away because of cancer 同义句in 1993,Audrey Hepburn--------- ------- cancer Cancer (死于）thousands of people every year some characteristics of people were born under Cancer.怎么译 It's reported that smoking m___ his risk of cancer. one of four will get cancer,is it true?