熔断器在电力拖动控制电路中起（）保护。
A.短路保护
B.过载保护
C.欠压保护
D.接地保护
参考答案：A
The people living in that apartment have free to that swimming pool.They don't have to be charged.
A．time
B．access
C．entrance
D．care
动脉导管未闭与室间隔缺损的鉴别要点是
A．有反复呼吸道感染
B．生长发育落后
C．左心室增大
D．肺动脉瓣区第二音亢进
E．以上均不是
