单项选择题
A.闪燃 B.燃点 C.自燃点 D.爆炸浓度极限
A.30℃ B.45℃ C.60℃ D.70℃
A.18%~21% B.10%~18% C.8%~10% D.6%~8%
A.380V B.220V C.36V D.12V
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