问题：
[单选] The external circumference of a pair of main bearing shells is slightly （） that of the bore of the housing which receives them Whats the meaning of “that” in the sentence above？
less than。lighter than。larger than。smaller tha。
问题：
[单选] The external circumference of a pair of main bearing shells is slightly larger than that of the bore of the housing which receives themThe difference is termed （）.
nip。nap。gap。li。
问题：
[单选] The figure that the volume of air at BDC is divided by the volume of air at TDC is termed as（）.
ignition ratio。power ratio。compression ratio。injection ratio。
问题：
[单选] The film of oil between the rings and the liner is not only essential for the lubrication but also plays an important part in achieving （）.
an oil seal。removing heat。a gas seal。cooling the pisto。
问题：
[单选] The film of oil between the rings and the liner is not only essential for the lubrication but also （） achieving a gas seal.
play a great part on。run a role in。plays an important part in。acts as important part at。
问题：
[单选] The fine filters will be arranged （） one can be cleaned while the other is operating.
in order to。because of。so that。so as to。
问题：
[单选] The four strokes are called suction, compression, expansion and exhaust, but only （） stroke provides the power to drive the ship.
suction。compression。expansion。exhaust。
问题：
[单选] The four-stroke engine is used for （） and sometimes for main propulsion with a gearbox to provide a propeller speed of between 90 to 120 rev/min.
alternator。turbo-charger。remote controller。windla。
问题：
[单选] The fourth engineer accompanied by the workers on oil barge measures the oil levels, temperature and （） in the tanks.
tank table。trim。water contents。oil pressure。
问题：
[单选] The fresh air coming in through the inner air ports, is compressed by（） to a higher pressure.
the cylinder head。the cross-head。the moving piston。the stationary pisto。
