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

Which of the two events listed occurs simultaneously in a two-stroke/cycle diesel engine?（）

How many power strokes per crankshaft revolution are there in an eight cylinder, two stroke/cycle diesel engine?（）

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

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 （）.

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

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

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

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