Feeling lonely may have some effects on a child's characters, however, it is not always permanent.
A:negative
B:positive
C:reasonable
D:beneficial
在图所示的电路中,电源电压为6V且不变,电阻R2为15Ω。求:①电流表A2的示数I2。②闭合电键S时,若电流表A1的示数变化了0.6A,则电阻R1的阻值。
following, speech, corn, pioneer