单项选择题
Vessels shall be deemed to be in sight of one another only when one（）from the other.
A.can be observed visually B.can be observed by radar C.can be located on the radar D.can be heard
单项选择题 Vessel underway means that a vessel is（）.
单项选择题 Vessel constrained by her draught is（）.
单项选择题 Underway vessels shall at all time maintain a proper look-out（）.
