时差N小时 口臭是如何引起的?

Morning breath is a topic of many jokes, and a real boon¹ to the mouth wash and toothpaste industries. But what exactly causes the foul² taste and odor in your mouth when you wake up in the morning? The most basic answer to this question is gravity.

早晨醒来后的口气既是一个笑柄，又是许多漱口水和牙膏企业的福音。但究竟是什么让你在一觉醒来之后，嘴里充满了难闻又讨厌的味道呢？这一问题的实质却在于地球引力。

If you've eaten fewer than three hours before you go to sleep, your stomach hasn't had time to digest all of your food. When you lie down, gravity causes the gastric³ juices that are busy digesting your food to come up into your throat. Because your airway⁴ and food pipe are side-by-side, they share an adjoining wall. Those gastric juices that have backed up in your food pipe actually permeate⁵ that wall and enter into your air pipe. These juices can irritate your larynx, and cause your voice to be hoarse⁶ and your breath to turn foul.

如果你吃了东西后不到三小时就上床睡觉了，那么你的胃就没有时间来消化所有的食物。当你躺下后，正在消化食物的胃液在引力作用下涌向你的喉咙。由于你的气管和食道是并排的，它们之间只有一层隔膜，所以当胃液流回食道时，实际上有部分胃液通过隔膜，渗透进了气管。正是这些胃液使你感到喉咙不适，并让你的声音变得沙哑，口气变臭。

In addition, gastric juices are acidic enough to burn the mucous⁷ membranes⁸ in your throat, resulting in a sore throat that occurs in the mornings, but lessens⁹ throughout the day. Morning mouth tends to worsen with age, because as you get older, the top of your esophagus, the thin tube that leads from the mouth to the stomach, loosens. With the softening¹⁰ of the top of this tube, gastric juices can more easily escape from the esophagus into the air pipe.

此外，胃液的酸性太强足以伤害到你的喉咙粘膜，导致早起时喉咙疼痛，不过一天下来这种疼痛会减轻。随着年龄的增长，早起时的口气会越来越重，这是因为随着年龄增大，你的食道顶部（也就是连接你的口腔和胃部的薄管）会变得越来越松。随着食道顶部越来越宽，胃液从食道进入气管也变得更容易了。

Another contributing factor to morning breath is infrequent swallowing during sleep. Swallowing allows us to keep our mouth relatively¹¹ free from odor-producing bacteria. But when we're asleep, these bacteria can thrive, contributing to the bad taste in our mouth when we wake up.

另一个造成早晨口气的重要原因就是在睡觉的时候偶尔咽唾液。吞咽使我们的口腔能够相对减少口臭引起的细菌。然而当我们睡熟时，这些细菌就会大量繁殖，因此我们醒来后的口气非常的难闻。

1 boon   

n.恩赐，恩物，恩惠

参考例句：

• A car is a real boon when you live in the country.在郊外居住，有辆汽车确实极为方便。
• These machines have proved a real boon to disabled people.事实证明这些机器让残疾人受益匪浅。

2 foul   

adj.污秽的；邪恶的；v.弄脏；妨害；犯规；n.犯规

参考例句：

• Take off those foul clothes and let me wash them.脱下那些脏衣服让我洗一洗。
• What a foul day it is!多么恶劣的天气！

3 gastric   

adj.胃的

参考例句：

• Miners are a high risk group for certain types of gastric cancer.矿工是极易患某几种胃癌的高风险人群。
• That was how I got my gastric trouble.我的胃病就是这么得的。

4 airway   

n.空中航线，通风口

参考例句：

• Lay them on their side and ensure the airway is unobstructed.让他们侧躺着，并确保呼吸道畅通。
• There is a purple airway in London Airport.伦敦机场里有一条皇家专用飞机跑道。

5 permeate   

v.弥漫，遍布，散布；渗入，渗透

参考例句：

• Water will easily permeate a cotton dress.水很容易渗透棉布衣服。
• After a while it begins to permeate through your skin.过了一会，它会开始渗入你的皮肤。

6 hoarse   

adj.嘶哑的，沙哑的

参考例句：

• He asked me a question in a hoarse voice.他用嘶哑的声音问了我一个问题。
• He was too excited and roared himself hoarse.他过于激动，嗓子都喊哑了。

7 mucous   

adj. 黏液的，似黏液的

参考例句：

• Healthy,skin,mucous membranes,and cilia are natural barriers to many viruses.健康的皮肤，粘膜和纤毛是许多病毒的天然屏障。
• Seromucous glands contain both mucous and serous cells.浆粘液腺既含有粘液性细胞，又含有浆液性细胞。

8 membranes   

n.（动物或植物体内的）薄膜( membrane的名词复数 )；隔膜；（可起防水、防风等作用的）膜状物

参考例句：

• The waste material is placed in cells with permeable membranes. 废液置于有渗透膜的槽中。 来自辞典例句
• The sarcoplasmic reticulum is a system of intracellular membranes. 肌浆网属于细胞内膜系统。 来自辞典例句

9 lessens   

变少( lessen的第三人称单数 )； 减少（某事物）

参考例句：

• Eating a good diet significantly lessens the risk of heart disease. 良好的饮食习惯能大大减少患心脏病的机率。
• Alcohol lessens resistance to diseases. 含有酒精的饮料会减弱对疾病的抵抗力。

10 softening   

变软，软化

参考例句：

• Her eyes, softening, caressed his face. 她的眼光变得很温柔了。它们不住地爱抚他的脸。 来自汉英文学 - 家（1-26） - 家（1-26）
• He might think my brain was softening or something of the kind. 他也许会觉得我婆婆妈妈的，已经成了个软心肠的人了。

11 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。