A.平時(shí)閥門關(guān)閉 B.當(dāng)液體壓力超過最大值時(shí)才打開 C.平時(shí)閥門打開 D.當(dāng)液體壓力達(dá)最大值時(shí)才關(guān)閉
A.10; B.8; C.5; D.3;