单项选择题
In a river subject to tidal currents，the best time to dock a ship without the assistance of tugs is（）.
A.at high water B.when there is a following current C.at slack water D.at flood
单项选择题 If your vessel is dragging her anchor in a strong wind，you should（）.
单项选择题 If you were being assisted by an icebreaker and he sent you the single letter Q，he would be telling you（）.
单项选择题 If you wear extra clothing when entering the water after abandoning ship it will（）.
