单项选择题
A.100 B.200 C.300 D.400
A.0.1 B.0.3 C.0.5 D.0.7
A.孔深＜1.8 B.1.8≤孔深＜2.5 C.2.5≤孔深＜5.0 D.孔深≥5.0
A.4%～6% B.5%～7% C.6%～8% D.7%～9%
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