单项选择题
When latitude and longitude are used，these shall be expressed in（）（and decimals of a minute if necessary），north or south of the Equator and east or west of Greenwich.
A.Fathoms and meters B.Miles and kilometers C.Arc and degrees D.Degrees and minutes
单项选择题 What is an ebb current（）.
单项选择题 What is a lighted safe water mark fitted with to aid in its identification（）.
单项选择题 What describes a flood current（）.
