问题：
[单选] A gudgeon pin in a trunk piston may be free to float and rotate, with （） to limit axial movement.
split pins。crankpins。dipsticks。circli。
问题：
[单选] A heater in the circuit facilitates warning of the engine prior to （） by circulating hot water.
starting。stopping。to start。to sto。
问题：
[单选] A high temperature alarm or （） which will melt is used to guard against the explosion of compressor air pipelines.
a flame trap。a relief valve。a fusible plug。a bursting ca。
问题：
[单选] A hot air start pipe indicates that there is （）.
inefficient cooling。a leaking air start valve。a clogged drain valve。a leaking air bottle。
问题：
[单选] A level gauge for a tank is to （）.
give the pressure。give the contents。give the shape of the tank。give the accuracy level。
问题：
[单选] A lubricant often has to perform many duties in any situation, in addition to its fundamental job of （）.
resisting oxidization。reducing friction。promoting moving speed。developing inertia。
问题：
[单选] A main bearing consists of two shells which are secured by means of studs and （）.
tie rods。through bolts。lead wires。bearing ca。
问题：
[单选] A number of cylinder liners are enclosed in one cast iron casing to form a （）.
cylinder cover。cylinder block。cylinder frame。bed-plate。
问题：
[单选] A separate piston cooling system is used to limit any contamination （） piston cooling glands（） the piston cooling system only.
between；to。either；or。from；to。neither；nor。
问题：
[单选] A single piece（） fitted with bronze rings guides the piston in the cylinder liner.
piston skirt。piston crown。guide way。cross-head。
