问题描述：
[单选]
Before an auxiliary boiler is shutdown for an extended period of time， the water in the boiler should have a pH value of（）．
A．10
B．7
C．4
D．1
参考答案：查看无
答案解析：无
☆收藏
答案解析：无
☆收藏
上一篇：The purpose of the delivery check valve used in a diesel fuel injection jerk pump is to（）．
下一篇：If over a period of weeks the air-box pressure of a turbo-charged， diesel engine， operating at full load， appears to be dropping off， the cause can be（）．
- 我要回答: 网友(216.73.216.96)
- 热门题目: 1.活塞杆的中心线与十字头销的中 2.活塞裙外圆与活塞杆外圆的同轴 3.二冲程十字头式柴油机活塞运动