单项选择题
A.attached to the indicators B.opened C.closed D.broken
When to remove scale from the cooling spaces, acid solu...
单项选择题When to remove scale from the cooling spaces, acid solution （） in the system can be tested from time to time by putting some on to a piece of lime.
A.strength B.dense C.percentage D.velocity
When the water produced from most evaporator is supplie...
单项选择题When the water produced from most evaporator is supplied for drinking purpose, it must be treated to ensure it is biologically pure and （）.
A.slightly acidic B.slightly alkaline C.no salty D.slightly bitter
When the starting air valve closes on one cylinder, ano...
单项选择题When the starting air valve closes on one cylinder, another starting air valve has （） opened on another cylinder whose piston has just commenced its downward stroke.
A.just B.nearly C.merely D.already
