Free radicals are produced continuously as cells go about their daily business, and are churned out en masse when cells come under stress.

当细胞进行其日常活动时就会一直生成自由基，而当细胞受到压力时大量自由基会同时涌现。

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Gluten-free lifestyles have become increasingly en vogue among the general populace as well as elite athletes.

WSJ: The Breakfast of This Champion? Bacon, Hold the Eggs

Differential tax rates on lead-free petrol have encouraged drivers to switch en masse to it.

ECONOMIST: British election briefing: Transport