单项选择题
A.5MPa B.10MPa C.15MPa D.20MPa
A.40% B.50% C.60% D.75%
A.20mm B.15mm C.5mm D.10mm
A.+5mm或-5mm B.+10mm或-5mm C.+15mm或-10mm D.+10mm或-15mm
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