Either a low injection pressure or a leakage of piston rings is able to lead （）.
举一反三
- The piston rings are manufactured with a diameter （） the bore of the cylinder.
- These piston rings are so badly worn that they must be （）.
- Among the rings of a piston the （） one is subjected to the greatest load and temperature.
- The sealing rings are in four parts and pressed together around the piston rods by means of （）.
- The high pressure in fuel injection system of the diesel engine is produced by the （）.