为了降低冬季运行费用，有必要寻找廉价的外碳源。

It is necessary to look for low-cost external carbon sources for reducing the operating cost in winter.

youdao

为了降低冬季运行费用，有必要寻找廉价的外碳源。

It is necessary to look for low-cost external carbon sources for reducing the operating cost in winter.

youdao