单项选择题
A.等待2~3 min B.等待5min C.等待15min D.无需等待
A.1/5 B.1/4 C.1/3 D.1/2
A.无烟煤 B.焦煤 C.肥煤 D.贫煤
A.贫煤、瘦煤、焦煤、肥煤 B.褐煤、长焰煤、气煤、肥煤 C.气煤、无烟煤、肥煤、焦煤 D.焦煤、肥煤、不粘煤、无烟煤
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