单项选择题
A.Selected Worldwide Marine Weather Broadcasts
B.your local newspaper
C.the Notice to Mariners
D.the daily weather map
单项选择题 Compared to internal structural plating，the exterior hull plating on a ship is usually（）.
单项选择题 Compared to a low pressure system，generally the air in a high is（）.
单项选择题 Commercial ships or other persons or agencies requiring the assistance of Canadian Coast Guard icebreakers should first contact（）.