For example, they'll break proteins into their component amino acids
比如，它们会把蛋白质分解成氨基酸成分，
and then break those down even further into various compounds.
然后再把这些更进一步分解成各种化合物。
Some of the foul-smelling byproducts of these reactions,
这些反应中产生的一些难闻的副产品，
such as hydrogen sulfide and cadaverine, escape into the air and waft their way towards unsuspecting noses.
比如硫化氢和尸胺，会逃进空气中并一路飘到毫无戒备的鼻子里。
Our sensitivity to these odors and interpretation of them as bad smells may be an evolutionary mechanism
我们对这些气味的敏感度以及将它们认知为难闻气味的行为也许是一种进化机制，
warning us of rotten food and the presence of disease.
提醒我们注意腐坏的食物和疾病的存在。
Smell is one of our most intimate and primal senses, playing a huge role in our attraction to potential mates.
嗅觉是我们最私人和原始的感官之一，它在我们吸引潜在配偶时发挥着巨大的作用。
In one poll, 59% of men and 70% of women said they wouldn't go on a date with someone who has bad breath,
在一项民意测验中，59%的男性和70%的女性表示他们不会和有口臭的人约会，
which may be why Americans alone spend $1 billion a year on various breath products.
而这也许就是美国人一年在各种除口臭产品上的花费达十亿美元的原因。
Fortunately, most bad breath is easily treated.
好在大部分口臭问题都很容易对付。
The worst smelling byproducts come from gram-negative bacteria
最难闻的副产品是由革兰氏阴性菌产生的，
that live in the spaces between gums and teeth and on the back of the tongue.
它们生活在牙床和牙齿之间，以及舌头背面的位置。
By brushing and flossing our teeth, using antibacterial mouthwash at bedtime,
只要刷牙和用牙线洁牙，上床睡觉前使用杀菌漱口水，
gently cleaning the back of the tongue with a plastic scraper and even just eating a healthy breakfast,
用塑料刮板轻轻地清洁舌背，甚至只是吃一顿健康的早餐，
we can remove many of these bacteria and their food sources.
我们都能清除很多细菌及它们的食物来源。
In some cases, these measures may not be enough due to dental problems, nasal conditions, or rarer ailments, such as liver disease and uncontrolled diabetes.
在某些情况下，由于牙齿问题、鼻腔情况或像肝病和糖尿病这样的较罕见疾病，这些措施也许远远不够。
