能见度不良，船长12米及以上的客渡船航行时，如何用声号表明“我是客渡船”？
参考答案：发出二短一长的声号表明“我是客渡船”。
0.75______0.8 5.69______56.9 7.217______7.22
6.04______6.004 0.9______0.839 3.50______3.6．
What is the meaning “speed is not of primary importance”?（）
A.Speed is important
B.Speed is not the most important
C.Speed is mainly important
D.Speed is first importan
