如图所示，已知电阻R1=3Ω、R2=6Ω，电流表A1的示数是0.4A，则电流表A的示数是______A．
∵R1、R2并联
∴R2支两端的电压为U2=U1=I1R1=0.4A×3Ω=1.2V，
R2支路的电流I2=
=U2 R2
=0.2A，1.2V 6Ω
∴干路电流为I=I1+I2=0.4A+0.2A=0.6A，即电流表的示数为0.6A．
故答案为：0.6．
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| Not long before, my daughter's shoes were scratched (划破) with a knife. She burst into tears. I took them to the shoemaker's. The young apprentice(学徒) glanced at the 1 and said, "Nothing I can do except 2 the upper." His master looked at them and said, "If you 3 me, I will add more scratches on both the shoes." I was 4 and asked why. He explained,"As if the opening were made 5 for a special style." I didn't fully understand him, 6 I decided to leave the shoes. Two days later I dropped by from work to 7 the shoes. I found more scratches on each shoe; all the openings were patched (缝补)by soft red leather; the stitches (针脚) were twisted with the appearance looking more 8 and interesting than ever. I couldn't help praising the master's 9 . Another time, my sister's blouse was torn, leaving a large opening. My wife checked it 10 , and then said, "Let me take it home and 11 it." Three days later, seeing it again, I was greatly 12 : all the torn parts took on a look of ice crystal (水晶); attached to it was a snowman made of flowery rags. I sighed with 13 ,"It's amazing!" "I was 14 by that shoemaker. Patches are supposed to be 15 , but a skillful craftsman (工匠) can make it take on a kind of 16 ." replied my wife. Her words inspired me more: perfection is impossible to achieve in 17 ; patches appear in the 18 of injury, disability or disease. Since you can't change the existence of wound, you should not 19 people's sympathy by disclosing the wound, which is meaningless. Just sew the 20 by patches and produce a most beautiful flower on it, and that is the significance of life. | ||||
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