单项选择题
A metal ring on the bottom of a block，to which the standing part of a tackle is spliced，is known as a(n)（）.
A.becket B.loop C.swivel D.eye
单项选择题 A metal object on the pier resembling a tree stump and made to receive mooring lines is a（）.
单项选择题 A metal eye spliced into a wire is called a（）.
单项选择题 A ketch is a sailing vessel with（）.
