We need to know that energy consumption represents the single largest controllable operating expense for a building, typically a third of variable expenses.

我们应当认识到，能源消耗是建筑物的唯一一项最大的但可控制的营运费用，一般为可变费用的三分之一。

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According to statistics, travel expense has been the second biggest controllable cost, which is next to human resource, in enterprise operation.

据统计，差旅成本已成为企业运营中次于人力成本的第二大可控成本。

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The biggest expense is advertising, which is significant at about 27% of revenues, but it is also very controllable and can be cut when times are tight to preserve profit margins.

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