单项选择题
A.Grooves B.Recesses C.Ridges D.Nips
（） are fitted in the exhaust system and facilitate char...
单项选择题（） are fitted in the exhaust system and facilitate charge removal and scavenging in each cylinder.
A.Diffusers B.Compressors C.Steam boilers D.Soot blowers
（） provide the water to the pistons.A.Pneumatic pipesB....
单项选择题（） provide the water to the pistons.
A.Pneumatic pipes B.Hydraulic pipes C.Telescopic pipes D.Operating gas pipes
（） is used for washing and drinking.A.The ballast syste...
单项选择题（） is used for washing and drinking.
A.The ballast system B.The salt water system C.The bilge system D.The domestic system
