271 活塞環壽命一般為幾小時(hrs)?
(A)4,000~6,000hrs
(B)6,000~8,000hrs
(C)8,000 ~10,000hrs
(D)10,000~12,000hrs

答案：登入後查看
統計： A(2), B(1), C(42), D(2), E(0) #1307992