A:that; what; all
B:what; that; that
C:that; that; that
D:what; that; what
若已知太阳的一个行星绕太阳运转的轨道半径为r,周期为T,引力常量为G,则可求( )
如图是显微镜结构图,请据图回答:(注:内填序号)
要保护环境就必然要停止对资源的开发利用。( )
画一个底是3厘米,高是2厘米的平行四边形.
Mrs Lin advised the students ______ with friends online and said it was a waste of time.