9. 一般活塞環自由開口a與環直徑D的關係為？
(A)a = (0.01 ~ 0.03)D mm
(B)a = (0.05 ~0.08)D mm
(C)a = (0.10 ~ 0.13)D mm
(D)a = (0.30 ~ 0.5)D mm

答案：登入後查看
統計： A(29), B(8), C(38), D(10), E(0) #2711691