单项选择题
The Vessel Bridge-to-Bridge Radiotelephone Act applies to which towboat?（）
A.A 100 GT towboat，24 feet in length B.A 90-foot towboat tied to the pier C.A 60-foot towboat towing by pushing ahead D.A 400 GT towboat anchored
单项选择题 The Vessel Bridge-to-Bridge Radiotelephone Act applies to（）.
单项选择题 The unit of duration of a dash in Morse Code is（）.
单项选择题 The range of a SSB transmission is MOST affected by（）.
