单项选择题
Which factor has the greatest effect on the amount of gain required to obtain a fathometer reading?（）
A.Salinity of water B.Temperature of water C.Atmospheric pressure D.Type of bottom
单项选择题 The standards of physical and medical fitness established by the Party shall not ensure that seafarers（）.
单项选择题 The maneuverability of the ship is considered（）if the following criteria are complied with.
单项选择题 What does ECDIS stand for?（）
