63. The chain line in the industrial drawing is a line where long strokes and dots appear
alternately. The length of the long strokes is about
(A) 2mm
(B) 10mm
(C) 20mm
(D) 50mm
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統計: A(10), B(8), C(14), D(2), E(0) #2929640
統計: A(10), B(8), C(14), D(2), E(0) #2929640