单项选择题
A.before B.after C.when D.until
When entering a foam injected space （） breathing appara...
单项选择题When entering a foam injected space （） breathing apparatus.
A.put out B.put on C.take off D.take in
The exhaust ports are located around the lower part of ...
单项选择题The exhaust ports are located around the lower part of the cylinder liner, （）the products of combustion are driven by scavenging air.
A.in which B.by which C.through which D.from which
The main engine is cooled with fresh water （）is added s...
单项选择题The main engine is cooled with fresh water （）is added suitable small quantities of chemicals to prevent corrosion.
A.in which B.on which C.to which D.by which
