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

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

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

Control of the main propulsion diesel engines can be shifted from the engine room to the wheelhouse from the （）.

If a diesel engine is difficult to start and operates with the engine temperatures lower than normal, you should suspect that the （）.

What causes diesel fuel to be ignited in the cylinder of an operating diesel engine?（）

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

The ability of the governor to prevent fluctuations in engine speed is termed （）.

The highest pressure in a diesel engine cylinder normally occurs （）.

The minimum speed an engine must attain before ignition can occur depends upon （）.