单项选择题
A.30线/cm~40线/cm B.40线/cm~48线/cm C.54线/cm~60线/cm D.80线/cm~90线/cm
A.5%~10% B.10%~30% C.30%~60% D.70%~90%
A.强 B.弱 C.一样 D.较弱