单项选择题
A.2.5 B.3.0 C.3.2 D.3.5
A.1.522,0.427 B.1.522,0.472 C.0.592,0.427 D.0.592,0.529
A.4.8×104 B.5.2×104 C.5.9×104 D.6.2×104