单项选择题
If a tow sinks in shallow water，you should（）.
A.release it immediately B.attempt to beach it before it goes under C.pay out cable until it's on the bottom and place a buoy on the upper end D.shorten cable to keep it off the bottom
单项选择题 Ice blink is（）.
单项选择题 For operations in pack ice，a vessel should（）.
单项选择题 Before entering an ice area，the ship should be（）.
