Our use of fossil fuels is the main source of excess greenhouse gases.

我们对化石燃料的使用是温室气体过量的主要来源。

youdao

Water was the main source of mechanical power, and by the end of the seventeenth century, England alone is thought to have had some 20,000 working mills.

水是机械动力的主要来源，而到了17世纪末，人们认为仅英格兰就有2万个左右的工作磨坊。

youdao

The main source of income, tourism, is expected to dry up completely this summer.

作为主要收入来源的旅游业预计将在今年夏天彻底枯竭。

《柯林斯英汉双解大词典》

Mr. Bahtiarian says the main source of noise pollution is the propeller.

VOA: special.2011.06.29

Glucose has to get into cells, that's the main source of energy source that cells use, metabolism of glucose.

但葡萄糖又必须进入细胞,因为它是细胞能量的主要来源,即通过葡萄糖代谢产生能量

耶鲁公开课 - 生物医学工程探索课程节选

So the main business of government consists in knowing how to control the elites because they are always a potential source of conflict and ambition.

因此统治的第一要务在于,懂得如何控制精英人物因为,他们往往是冲突和野心的潜在来源。

耶鲁公开课 - 政治哲学导论课程节选

On balance, considering effects on the economy, the main source must be the consumption tax.

FORBES: Of Numbers and Choices

For most advisers, the main source of business comes from referrals from existing clients.

WSJ: Do You Make the Asset Cut?

The Guinea-Bissau army was the main source of weapons and ammunition for the MFDC.

BBC: Senegalese soldiers