单项选择题
A.green lights B.red lights C.yellow lights D.white lights
If your vessel were proceeding down river (descending)，...
单项选择题If your vessel were proceeding down river (descending)，a green square marker with a green reflector border on the right bank would be a（）.
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
