单项选择题
（） are two vertical supports，usually steel，one each side of the centerline of the ship used to support booms.
A.Shrouds B.King posts C.Stays D.Turnbuckles
单项选择题 What is the primary disadvantage of a permanent chain chaser system?（）
单项选择题 What is the main reason to slush a wire rope?（）
单项选择题 What is the best guide for determining the proper scope of anchor chain to use for anchoring in normal conditions?（）
