单项选择题
A.躯干 B.大腿和骨盆带 C.前臂 D.小腿 E.上臂和肩胛带
A.>100:1 B.50:1 C.10:1 D.5:1 E.1:1
A.10%~15% B.5%~10% C.1%~2% D.2%~3% E.3%~5%