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

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

Lube oil cannot be efficiently filtered if its （）.

When fuel oil has seriously contaminated a diesel engine lubricating oil, you should （）.

Lube oil filters remove contaminants more efficiently if the oil being filtered is （）.

Maximum horsepower of a diesel engine is attained （）.

An automated diesel engine should normally shut down due to （）

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

Diesel engine control can be obtained by the bridge （）.

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