单项选择题
The oil （） in the discharging water from oil water separator exceeds 15 PPM without alarm, because the coil was burnt out.
A.filter B.hole C.pollution D.content
单项选择题 The internal part of boiler should be cleaned by yard if found （）.
单项选择题 At normal sea going, we use （） instead of donkey boiler.
单项选择题 The soot blowers are operating in the oil fuel boiler the air/fuel ratio must （） throughout the action, and blowers greased after use.
