单项选择题
The construction portfolio may be included as part of the ship（）.
A.general plans B.operating manual C.builders documentation D.CCS file
单项选择题 The circular steel structure installed around the propeller of a towboat is the（）.
单项选择题 The bow thruster generally is ineffective at（）.
单项选择题 Structural bulkheads on a ship are usually（）.
