单项选择题
A semisubmersible which will not remain upright and will assume a list either to port or starboard is likely to have（）.
A.a large TCG B.a negative GM C.excessive ballast D.insufficient deck load
单项选择题 A disk with a horizontal line through its center，equivalent to the summer load line，is called the（）.
单项选择题 A deep draft VLCC (100，000 DWT+) navigating in a narrow channel or canal（）.
单项选择题 A current moving across a lock entrance toward the river or toward the dam is called a(n)（）.
