A. is loaded B. are loaded C. have loaded D. have been loaded
A. 防火 B. 防爆 C. 防雷
A. 中腐蚀 B. 完好 C. 轻腐蚀 D. 重腐蚀
A. 搅拌烟气 B. 补充空气 C. 促使燃料燃烧 D. 提供动力