47 Although production of Halon 1301 and Halon 1211 was discontinued in 1994, systems and
extinguishers were permitted to remain in service until suitable replacement agents were available.
(A)substitute
(B)existing
(C)alternative
(D)complement
答案:登入後查看
統計: A(1), B(0), C(1), D(0), E(0) #3478855
統計: A(1), B(0), C(1), D(0), E(0) #3478855