問題詳情
34. What is the fundamental frequency of the signal of whistlestipulated by COLREGS?
(A) Within the range 50~500 Hz.
(B) Within the range 60~600 Hz.
(C) Within the range 70~700 Hz.
(D) Within the range 80~800 Hz.
參考答案
答案：C
難度：困難0.238095
統計：A(3),B(6),C(5),D(4),E(0)