A.絕對(duì)壓力與大氣壓力之差 B.大氣壓力與絕對(duì)壓力之差 C.相對(duì)壓力與大氣壓力之差 D.大氣壓力與相對(duì)壓力之差
A.粘度較小 B.粘度較大 C.油性較好 D.潤(rùn)滑脂