元朝郭守敬在天文历法上的杰出成就是(     ) A.发明了测量经

元朝郭守敬在天文历法上的杰出成就是(    

A.发明了测量经线的科学方法         B.主持天文测量,编写了《授时历》

C.使中国古代历法体系成熟           D.留下了哈雷彗星与太阳黑子的最早记录

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