A.進(jìn)油閥滯后關(guān)閉，回油閥滯后開(kāi)啟
B.進(jìn)油閾滯后關(guān)閉，回油閥提前開(kāi)啟
C.進(jìn)油閥提前關(guān)閉，回油閥滯后開(kāi)啟
D.進(jìn)油閥提前關(guān)閉，回油閥提前開(kāi)啟

A.進(jìn)油閥滯后關(guān)閉，回油閥滯后打開(kāi)
B.進(jìn)油閥滯后關(guān)閉，回油閥提前開(kāi)啟
C.進(jìn)油閥提前關(guān)閉，回油閥滯后打開(kāi)
D.進(jìn)油閥提前關(guān)閉，回油閥提前開(kāi)啟