A.0in~1in B.1in~2.5in C.2.5in~3.5in D.3.5in~4in
A.履帶板磨損 B.吊機翻車幾率 C.履帶板銷孔磨損 D.吊機載荷
A.5mm B.10~20mm C.20~30mm D.30~40mm