单项选择题
Neglecting friction，you desire to lift a 300 kgs weight with a stress on the hauling part of 100 kgs.Which of the following tackles would you use（）.
A.Gun tackle B.Luff tackle C.Two-fold tackle D.Double-luff tackle
单项选择题 Manila slings should not be used to load（）.
单项选择题 Instead of whipping an end of a line，a temporary means of preventing the line from unraveling is to tie a（）.
单项选择题 If you were to pass a stopper on a wire rope，what should the stopper be made of（）.
