单项选择题
The speed of a vessel adjusted to that of a pilot boat at which the pilot can safely embark is（）.
A.ground speed B.boarding speed C.relative speed D.speed of the vessel
单项选择题 The step of a pilot ladder which prevents the ladder from twisting is the（）.
单项选择题 The term of landfall means（）.
单项选择题 Throwing overboard of goods in order to lighten the vessel or improve its stability in case of an emergency defines（）.
