焦炉护炉铁件的作用是什么？
参考答案：
焦炉的砌体是用耐火砖砌成的，护炉铁件起经常地、不间断地、分不合理地向焦炉砌体施加足够的保护性压力的作用。
对话排序。
A.—I like songs I can sing along with, too. What's your favorite band?
B.—Oh, look! There's the new Cool Kids CD.
C.—The lions. Their words are interesting.
D.—You are kidding. I think they are awful. I prefer music that has great lyrics and I can sing along with.
E.—Oh, yeah. They are my favorite band. I like music that I can dance to.
F.—The Cool Kids? Do you like them?
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下列物质属于电解质的是（）。
A.蔗糖
B.甲烷
C.乙酸钠
D.二氧化碳
