The human body hosts hundreds of bacterial species that perform various salubrious housekeeping chores, from aiding digestion to helping the immune system identify foreign invaders.

人类身体携带有几百种细菌物种，这些细菌负责各种有益健康的例行工作，从帮助消化到帮助免疫系统确认外来入侵物。

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Janitors and cleaners (except maids and housekeeping cleaners) perform a range of duties from cleaning floors to taking out the garbage to painting and carpentry.

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