A.升高; B.下降; C.不變; D.無(wú)對(duì)應(yīng)關(guān)系
A.越長(zhǎng); B.越短; C.不變; D.無(wú)對(duì)應(yīng)關(guān)系
A.打開(kāi) B.關(guān)閉; C.進(jìn)口閥打開(kāi),出口閥關(guān)閉; D.出口閥打開(kāi),進(jìn)口閥關(guān)閉