题目

— Well, ________, you did good job. You can go home.— Bye, Mr. Liu. A . that's OK B . that's it C . it's nothing D . it's all right 答案：B如图I1=2A，I2=1.5A，R1=12欧，R2=8欧，R3=3欧，求R3上的电流大小和方向。