单项选择题
A.cylinder cover B.cross-head shoes C.guide-ways D.scavenging boxes
The carbon deposits on the piston crown and in the ring...
单项选择题The carbon deposits on the piston crown and in the ring grooves （）.
A.should be scraped B.should be derusted C.should be drilled out D.to be brushed off
The cap and new shell are tightened up and then removed...
单项选择题The cap and new shell are tightened up and then removed and the thickness of the wire measured by （）.
A.a bridge gauge B.a micrometer C.a thermometer D.a indicator
The burning of the fuel adds more heat to the air charg...
单项选择题The burning of the fuel adds more heat to the air charge, causing it to expand and force the engine piston to do work on the crankshaftWhat does “it” mean in this sentence?（）
A.the burning B.the fuel C.the air charge D.the engine piston
