I can't find to sit on the crowded bus.
A:nowhere
B:somewhere
C:anywhere
D:everywhere
已知m,n是一元二次方程x2-4x-3=0的两个实数根,则m-2n-2为( ).
阻值为3Ω与6Ω的电阻,将它们串联,其总电阻为R1;将它们并联,其总电阻为R2,则R1∶R2等于()