单项选择题
A.UB=0V、Uc=2.3V、UE=1V B.UB=0.7V、UC=6V、UE=0V C.UB=0V、Uc=5V、UE=6V D.UB=5V、Uc=5V、UE=5V
A.A B.B C.C D.D
A.|θA|>|θc| B.|θA|=|θC| C.|θA|<|θC| D.不能确定