单项选择题
A.0.66gm-1hPa-1s-1B.0.66gm-1Pa-1s-1C.-0.96gm-1Pa-1s-1D.-0.96gm-1hPa-1s-1
A.日地距离B.大气透明度C.太阳高度角D.日照时间
A.(3)(4)B.(2)(4)C.(1)(3)D.(1)(2)