本初子午线是
A:地球仪上的任意一条经线
B:是东、西经度的分界线
C:地球仪上的任意一条纬线
D:是东、西半球的分界线
863计划纲要》,这表明中央对计划的态度是( )
While ____ the dog, you were careless and it got ____ and was hit by a car.