单项选择题
A.mile board B.dredging mark C.passing daymark D.crossing daymark
Environmental loading consists of the forces caused by ...
单项选择题Environmental loading consists of the forces caused by wind，waves，and（）.
A.drilling B.soil reactions C.temperature D.current
Entering from seaward，triangular-shaped daymarks are us...
单项选择题Entering from seaward，triangular-shaped daymarks are used to mark（）.
A.the starboard side of the channel B.the centerline of the channel C.an obstruction where the preferred channel is to starboard D.special purpose areas
During the day，a vessel with a tow over 200 meters in l...
单项选择题During the day，a vessel with a tow over 200 meters in length will show（）.
A.a black ball B.a diamond shape C.two cones，apexes together D.one cone，apex upward
