五、請將下列英文譯成中文。（20 分）On the compression stroke for a theoretical single cylinder compressor, the pressure risesto slightly above discharge pressure. A spring-loaded non-return discharge valve opensand the compressed air passes through at approximately constant pressure. At the end ofthe stroke the differential pressure across the valve, aided by the valve spring, closes thedischarge valve, trapping a small amount of high pressure air in the clearance spacebetween the piston and the cylinder head. On the suction stroke the air in the clearancespace expands, its pressure dropping until such time as a spring-loaded suction valvere-seats and another compression stroke begins.