单项选择题
A.当日 B.次日 C.当日和次日
A.National Reference Climatological Surface Station B.National Reference Climatological Station C.National Basic Meteorological Observing Station D.National Basic Meteorological observe Station E.National Ordinary Meteorological Observing Station
A.器差修正 B.重力修正 C.温度修正 D.湿度修正