我国水资源空间分布不均,主要表现在( )
A:南方多北方少,东部多西部少
B:南方多北方少,西部多东部少
C:东南多西北少,东北多西南少
D:山地多平原少,内陆多沿海少
Why not ____ your teacher for help when you can't finish _____ the story by yourself?
若x2+ax+b=(x+3)(x﹣4),则a=____ ,b=____ .
请回答下列问题