A:volleyball
B:football
C:basketball
Lucy _____ her kind mother and she often helps _____ sick kids in the hospital.
镁在氧气中燃烧的反应中,镁、氧气、氧化镁的质量比为( )
下图为某日太阳和月球分处地球两侧时光照简图,读图完成下题:
下列各点中,符合“西半球,北半球,低纬度”三个条件的是( )