图示稳压电路，稳压管Dz1的稳压值为5.5V，Dz2的稳压值为8.4V，这两个稳压管的正向压降均为0.6V，图示电路的输出电压Uz等于()V。
A. 5.5
B. 8.4
C. 9
D. 13.9
查看答案
沿长方体三个互不相交且互不平行的棱边分别作用有力 P1、P2、P3，它们的大小均为P，即P1=P2=P3，长方体的尺寸分别用a、b、c表示。当图所示力系P1、P2、P3，能简化为一合力时，长方体的尺寸a、b、c间的关系为()。
A. a=b-c
B. a=c-b
C. a=b+c
D. a=0.5(b+c)
The woman in the shop stared at them strangely, because______.
A. they had on funny clothes
B. she saw foreigners for the first time
C. she wondered why they had come into the shop
D. they didn't give her any money
A．Work for a radio station.B．Live in a dormitory.C．Take a long trip.D．Look for another
A. Work for a radio station.
B. Live in a dormitory.
C. Take a long trip.
D. Look for another one.
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