1×3=____ 4×4=____ 3×1=____ 2×1=____
____
如图所示,用控制变量法可以研究影响平行板电容器电容的因素.设两极板正对面积为S,极板间的距离为d,静电计指针偏角为θ(θ与电容器两板间的电压U成正比).实验中,极板所带电荷量不变,若( )
Why not ____ your teacher for help when you can't finish _____ the story by yourself?