- 搜標(biāo)題
- 搜題干
- 搜選項(xiàng)
單項(xiàng)選擇題
A viscosity regulator used for an engine is usually provided in order to （） for an engine burning heavy fuel oil.
A.regulate the fuel supply
B.maintain a constant fuel viscosity at the fuel valves
C.maintain efficient cooling
D.alter the fuel density
