In using reduction gears to obtain efficient propeller speeds, （）.

The main purpose of the piston oil scraper rings is to （）.

To determine if the lube oil filter elements need changing, （）.

When would the available energy of the exhaust gases of a two-stroke/cycle diesel engine be insufficient to drive an exhaust gas turbocharger, resulting in the incorrect amount of air for combustion?（）

For a given size engine, the two-stroke/cycle diesel engine will deliver more power than a four-stroke/cycle diesel engine because （）.

A diesel engine piston ring face is in direct contact with the （）.

Routine monitoring of a diesel engine should include （）.

In diesel engines, the four basic events (intake, compression, power and exhaust) are performed once in （）.

Combustion knock can occur in the cylinders of a diesel engine under any condition permitting （）.

Combustion knock occurring in a diesel engine can be caused by （）.