JT1型通用式机车信号主机的19芯信号插座除感应信号外，所有信号都用（）V电源信号。
A.5
B.24
C.50
D.110
参考答案：C
阅读短文，判断正 (T)误 (F) 。
Look! The man behind you is playing cards with his friends. The woman is singing. Li Ming is looking
for Danny. Danny is playing with the baby. The baby is laughing. They are having fun.
( ) 1. The man is laughing.
( ) 2. The woman is singing.
( ) 3. Danny is playing with the baby.
( ) 4. Li Ming is playing with the baby, too.
( ) 5. The baby is crying.
电泵井平均免修期计算公式是怎样的？
