Wood, the primary source of heat for homes and industries and also used in the iron industry as processed charcoal, was diminishing in supply.

木材是家庭和工业的主要热源，也以加工木炭的形式用于铁工业，它的正在减少。

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A fire requires fuel to burn, air to supply oxygen, and a heat source to bring the fuel up to ignition temperature.

一把火需要燃料来燃烧、空气来提供氧气还有使燃料到底燃烧温度的热量。

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The technicality and economy of heat source scheme of district heat-supply are analyzed and compared with a practical heat-supply scheme by economical analysis methods.

利用经济分析方法，结合实际供热工程，对区域供热热源方案的技术性、经济性进行了分析比较。

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