汽包锅炉如果水质不良,就会引起水汽系统结垢、()和()等故障。
参考答案:积盐金属腐蚀
I regret to have not paid more attention to our English lessons at school.
A.not paying
B.not having paid
C.have not paid
D.not to have paid
通信设施安装质量检测主要检测项目是()。
A.供电系统
B.接地电阻
C.绝缘性能
D.通信传输质量