单项选择题
The knot used to join two lines of different diameter is a（）.
A.square knot B.carrick bend C.becket bend D.sheepshank
单项选择题 The knot at the end of the heaving line used to pass the towing hawser is called a（）.
单项选择题 he heel block is located（）.
单项选择题 The disadvantage of using three strand nylon line for towing is its（）.
