单项选择题
The piston cooling system may employ similar components, except that a drain tank is used instead of a head tank That means this system （）.
A.doesnt use a drain tank but a head tank B.uses a drain tank not head tank C.uses a drain tank and a head tank D.uses neither a drain tank nor a head tank
单项选择题 The piston cooling system may employ similar components, except that （） is used instead of a head tank.
单项选择题 The pistons are cooled by oil supplied from the forced （） system.
单项选择题 The period when both inlet valves and exhaust valves are open is referred to as （）.
