What this means is that our lips have little to no protection from the environment, and their main source of moisture is the saliva that comes from our mouths.
这就说明嘴唇易受环境影响，而嘴唇水分大多是来自嘴里的唾液。
What's more, unlike much of the rest of our body, our lips are almost always on display, and rarely covered by clothing.
此外有别于身体其他部位，嘴唇直接暴露在外面。
As a result, the moisture on our lips is continually evaporating.
结果就造成嘴唇的水分一直在蒸发。
And that's before we take into account exposure to sun, wind, cold, and air-conditioning.
我们的嘴唇还要暴露于阳光、大风、冷空气及空调环境。
Plus, if you're sick or have allergies, and your nose is congested, your lips end up drying more quickly because you tend to breathe through your mouth.
此外，如果你生病或者过敏而鼻塞，嘴唇会干得更快，因为你不得不大口呼吸！
