問題詳情
51 In apparent backdraft conditions, the best time to attempt to enter is______ .
(A)immediately
(B)after ventilation has started
(C)before beginning of ventilation
(D)only after ventilation is completed
參考答案
答案：D
難度：適中0.407407
統計：A(7),B(6),C(3),D(11),E(0)