单项选择题
One of the signals，other than a distress signal，that can be used by a vessel to attract attention is a(n)（）.
A.red star shell B.searchlight C.burning barrel D.orange smoke signal
单项选择题 Generally，you can best keep a vessel under steering control when the vessel has（）.
单项选择题 Generally speaking，the most favorable bottom for anchoring is（）.
单项选择题 As a last resort，a tourniquet can be used to（）.
