The main culprit in the current crisis seems to be modern farming techniques.

当前这场危机的罪魁祸首好像是现代农业技术。

《牛津词典》

About 10% of Japanese teenagers are overweight. Nutritionists say the main culprit is increasing reliance on Western fast food.

约10%的日本青少年都超重。营养学家们称主要的原因是他们越来越依赖西方快餐。

《柯林斯英汉双解大词典》

Although the recession made everything worse, the internet is the main culprit.

尽管经济衰退让一切变得更糟，但互联网才是罪魁祸首。

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The majority of them, in hindsight, have identified a poor entry price as the main culprit.

FORBES: Avoiding Those Costly Impulsive Trades

The main culprit was an acquisition that looked like a good idea at the time.

FORBES: Magazine Article

Food prices were the main culprit, accounting for over half of the price increases.

FORBES: Even In Slow Economy, Brazilians Can't Escape Rising Prices