单项选择题
A.closed B.opened fully C.cracked open D.partly open
When start a screw pump, the by pass valve should be （）...
单项选择题When start a screw pump, the by pass valve should be （）.
A centrifugal pump can’t supply water after startingYou...
单项选择题A centrifugal pump can’t supply water after startingYou should check （）.
A.priming water B.power supply C.packing gland D.bearing lubrication
Open the （）of inter cooler before starting an air compr...
单项选择题Open the （）of inter cooler before starting an air compressor.
A.cylinder cover B.cooling water C.oil cup D.drain valve
