Your mother always in you, right?
A:take pride
B:take proud
C:takes pride
D:takes proud
如图所示,请画出光线通过透镜后的光路图.
解方程:2x2-4x-1=0 (用配方法)
串联后总电阻为10欧的两个电阻,并联后总电阻最大可达到( )