单项选择题
A.The density of the air entering the compressor
B.The temperature of the air entering the compressor
C.The designed rotating speed of the compressor
D.A leaking head gasket
单项选择题 In order to distribute the side pressures over a wide area of the cylinder walls and liners, which of the listed types of pistons are used in modem low pressure air compressors?（）
单项选择题 A cracked diaphragm in a thermostatic expansion valve will cause the valve to （）.
单项选择题 If an air compressor is used to supply air primarily to the combustion control system and other pneumatic controllers, the entire system is known as the （）.