（） are formed by abrasive particles entering the bearing and scoring the shaft.

（） 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

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（） provide the water to the pistons.

A.Pneumatic pipes
B.Hydraulic pipes
C.Telescopic pipes
D.Operating gas pipes

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