单项选择题
A.2.5Mpa B.3.0MPa C.3.5MPa D.4.0MPa
A.15 B.20 C.12 D.10
A.1 B.0.1 C.0.05 D.0.01
A.四舍五入 B.基准修约 C.五五修约 D.四舍六入五单留
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