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

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

Electrically operated safety devices on auxiliary diesel engines function to stop the engine by （）.

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

The function of diesel engine piston compression rings is to （）.

In a simple mechanical governor, the （）.

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

Proper filtering and straining of fuel oil is important because the （）.

White smoke exhausting from an operating diesel engine may indicate （）.

If the water level dropped rapidly in the expansion tank of a closed diesel engine cooling water system, you should suspect a （）.