Before pumping up the crankcase oil,（） should be worked by hand to minimize corrosive action on the liners.

[单选题]E．xcessive oil foaming in the crankcase of a refrigeration compressor is most likely to occur when the compressorA．has run continuously for a long periodB．suction pressure is below normalC．oil level is below normalD．starts after a long idle period

[单选题]A diesel engines crankcase oil level is found to be too high√ You should suspect that （）.A . the engine was over filledB . there might be a fuel leakC . there might be a water leakD . all of the above

[单选题]“Before disconnecting the oil pipe, would you flush the oil retained in the pipe?” asked the oil barge owner （）A . by using of fresh waterB . with compressed airC . by using of sea waterD . with chemical compound

[填空题] LOW OIL LEVEL COMPR CRANKCASE LSLL-731表示（）。

[单选题]Dirty oil must be （） before being used again.A . mixed with clean oilB . purifiedC . heatedD . strained

[单选题]In cleaning up an oil spill, the use of chemical agents would______.A．absorb the oil for easy removalB．remove the oil from the waterC．disperse or dissolve the oil in the waterD．not affect the oil

[主观题]was hold up on my way back. Just before I 79

[试题]was hold up on my way back. Just before I________ 79

[单选题]The world's oil supplyA． haven been gradually being exhaustedB． is being gradually exhaustedC． is gradually exhaustedD． has gradually exhausted

[单选题]—I always look out before crossing the street.—You are right. You can't be too______.A． nervousB． carefulC． carelessD． hurried