单项选择题
The head of the bend is the（）.
A.top or upstream beginning of a bend B.bottom or downstream beginning of a bend C.midpoint or center radius of a bend D.center line or apex of a bend
单项选择题 The firing of a red star signal may mean（）.
单项选择题 The Coordinator Surface Search in a SAR situation should display by day（）.
单项选择题 Some sea water came into the wheel house during the voyage due to（）the window thereof.
