单项选择题
A.80% B.90% C.70% D.75%
A.15~20mm B.5~10mm C.8~13mm D.10~15mm
A.2类 B.3类 C.4类 D.5类
A.压力为0.25-0.32MPa B.压力为0.22-0.26MPa C.压力为0.28-0.32MPa D.压力为0.30-0.34MPa
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