A.4799 B.4865 C.4644 D.4523
A.進(jìn)氣閥開排氣閥關(guān) B.雙閥關(guān)閉 C.進(jìn)氣閥關(guān)排氣閥開 D.雙閥開
A.1855 B.1820 C.1778 D.1775