单项选择题
A disk with a horizontal line through its center，equivalent to the summer load line，is called the（）.
A.deadrise mark B.maximum allowable draft mark C.plimsoll mark D.tonnage mark
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)（）.
单项选择题 A common occurrence when a vessel is running into shallow water is that（）.
