单项选择题
A.give flexibility B.support the strands laid around it C.allow some circulation around the strands D.allow lubrication inside the rope
Neglecting friction，you desire to lift a 300 kgs weight...
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
Manila slings should not be used to load（）.A.cottonB.lu...
单项选择题Manila slings should not be used to load（）.
A.cotton B.lumber C.steel D.tires
Manila lines in which the strands are right-hand laid（）...
单项选择题Manila lines in which the strands are right-hand laid（）.
A.should be coiled in a clockwise direction B.should be coiled in a counterclockwise direction C.may be coiled either clockwise or counterclockwise D.should never be coiled
