It is a proven fact that fluoride strengthens growing teeth.

氟化物可以强化生长中的牙齿，这是已证明的事实。

《牛津词典》

This is a proven fact by everyone in the world.

这是一个被世人都证明的事实。

youdao

It has been a proven fact that women speak more frequent than men.

已经有事实证明女人讲话的频率比男人的高。

youdao

So if you guys have had-- many health professionals say that there's not enough nutrition education out there, that most people don't learn it in the schools, people aren't getting it so much from families because families don't know a lot about nutrition, but the fact is you've had a lot of nutrition education and you've just proven it.

也许大家听说过,很多健康专家声称,现在的营养教育很匮乏,许多人在学校里学不到这方面的知识,在家里也得不到多少这类信息,因为很多家长对营养一知半解,但事实上你们已接受了大量的营养知识,刚才你们已经证明了这点

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

It is a proven fact that specialization is guaranteed to increase efficiency.

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It is a proven fact that those whom are convicted and sentenced for sex offenses have less than a 8% chance to reoffend sesxually within the first 3 years after release from confinement.

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It's a science-proven fact (or, at least, there's a study supporting it): Social networks like Facebook increase jealousy, partly because information is much more accessible, and that information can often be ambiguous.

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