单选:锅炉的受热面上结有水垢后,由于水垢的导热性能比金属性能差(),就会影响锅炉的传热效率。

题目内容:
锅炉的受热面上结有水垢后,由于水垢的导热性能比金属性能差(),就会影响锅炉的传热效率。
A.几倍
B.十几倍
C.几十倍
D.百倍
参考答案:

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