阿摩線上測驗
28. The large boiler, along with extensive piping, valves, and __________ are required for safe operation.
(A)insulation
(B)lubrication
(C)injection pump
(D)turbo-charger
答案：登入後查看
統計： A(1), B(0), C(0), D(2), E(0) #3479072
統計： A(1), B(0), C(0), D(2), E(0) #3479072
