为防止变压器内部严重故障时,油流不稳定造成不能可靠跳闸,变压器瓦斯保护的出口中间继电器()。
A、必须有保持回路
B、不能有保持回路
C、无要求
参考答案:A
_____ his own study with his classmates, Xiao Li found he had fallen far behind. [ ]
A. Comparing
B. Compared
C. Comparing with
D. Compared with
不属于湿啰音特点的是()
A.断续
B.短暂
C.连续多个
D.性质不变
E.部位易变