单项选择题 On the top of the cylinder is mounted the cylinder cover which is pressed onto （） of the cylinder liner by means of nuts and studs.

单项选择题 On opposite ends of a single shaft of a turboblower are a gas driven （）and a air compressor, which are sealed each other.

单项选择题 On a four-stroke diesel engine, when the piston is driven downwards by the expanding gas, it delivers power to the crankshaft through the （）.