32. When there is danger of the passage of foreign matter, which may obstruct valves or piping, or damage machinery, so what element should be fitted in the pipe-lines?
(A) Flange
(B) Strainer
(C) Ejector
(D) Salinometer

答案：登入後查看
統計： A(44), B(109), C(41), D(14), E(0) #1973900