The step of a pilot ladder which prevents
题型:单项选择题
问题:
The step of a pilot ladder which prevents the ladder from twisting is the ().
A.Proof bar
B.Shifting bar
C.Long bar
D.Spreader
The step of a pilot ladder which prevents the ladder from twisting is the ().
A.Proof bar
B.Shifting bar
C.Long bar
D.Spreader