Jennifer is five years old now and she can dress h ____ every morning.
一只电流表的满偏电流Ig=1mA,内阻为500Ω,要把它改装成一个量程为10V的电压表,则应在电流表上( )
若x=1是一元二次方程x2+2x+m=0的一个根,则m的值为( )