单项选择题
The vertical movement of a vessel in the water is called（）.
A.pitch B.sway C.heave D.roll
单项选择题 The time required to incline from bow down to stern down and return to bow down again is called（）.
单项选择题 The principal action in changing from transit to survival draft in the event heavy weather threatens is（）.
单项选择题 The preferred method of controlling external bleeding is by（）.
