单项选择题
The standing part of a tackle is（）.
A.all the fall except the hauling part B.the hook that engages the weight to be moved C.that part to which power is applied D.that part of the falls made fast to one of the blocks
单项选择题 The square knot is used for（）.
单项选择题 The size of wire rope is determined by the（）.
单项选择题 The signal man assisting a crane operator has his arm extended with his fingers closed and thumb pointing upward. This is the signal to（）.
