四风机正常运行时，主油泵手动运行，副油泵控制开关置于自动，当主油泵跳闸或风机冷却油压低于（）时，副油泵自动启动。
参考答案：0.08MPa
It was when searching for the lost book whose cover was missing ______ a secret letter addressed to his mother.
A．what he found
B．until he found
C．that he found
D．he had found
低压断路器瞬动电流必须( )系统尖峰电流
A．小于
B．大于
C．等于
D．小于或等于
