Billions of years ago, free-living bacteria are thought to have become incorporated into living cells as energy-providing mitochondria.

据测在数十亿年前，一些自由生活的细菌进入到活细胞内部，变为负责提供能量的线粒体。

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Next time you're looking for a relatively bacteria-free place to store your lunch, consider that the bathrooms in your office are probably cleaner than the fridge.

如果下次你要找一个无菌的地方来存放你的午餐，考虑一下卫生间吧，或许那都比你的冰箱干净。

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Once the finished genome was inserted into the genome-free bacteria, the work regressed to the sort of microbiology that would have been familiar to the science's 19th-century pioneers.

最终的基因组注入无基因细菌之后，剩下的工作就只是那种19世纪科学先锋都很熟悉的微生物学了。

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