【英语时差8,16】酒精测试的原理

 How Do Breathalyzers Work? If a police officer sees you driving in a reckless manner, chances are you’ll be pulled over and asked to breathe into a special machine that measures your blood alcohol content. But how can your breath reflect how much alcohol is in your blood? Alcohol’s Affect On The Body The answer has to do with how alcohol is distributed throughout your body. Alcohol is a very small molecule¹ that can cross the membranes² of your body’s cells quite easily. Cellular³ membranes do not block the movement of alcohol molecules⁴ throughout the body. Once you take a drink, alcohol is absorbed into your blood stream and then distributed to various tissues. In the process of distribution, alcohol experiences few barriers and goes just about anywhere in equal concentrations. One of the places it ends up is in the air of our lungs. What Does A Breathalyzer Measure? A breathalyzer measures the amount of alcohol in your lungs. If you had taken a single swallow of beer right before the breathalyzer test, your breath might smell of alcohol, but the test would indicate that you were not intoxicated⁵. This is because the breath you would bring up from your lungs would not have any alcohol in it, even though the breath in your mouth might. Because the alcohol content of air in your lungs accurately⁶ reflects the alcohol content in the blood stream, law enforcement officers can use this information to know whether or not to take the keys from a driver who seems to be intoxicated.

1 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

2 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

3 cellular   

adj.移动的；细胞的，由细胞组成的

参考例句：

• She has a cellular telephone in her car.她的汽车里有一部无线通讯电话机。
• Many people use cellular materials as sensitive elements in hygrometers.很多人用蜂窝状的材料作为测量温度的传感元件。

4 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

5 intoxicated   

喝醉的，极其兴奋的

参考例句：

• She was intoxicated with success. 她为成功所陶醉。
• They became deeply intoxicated and totally disoriented. 他们酩酊大醉，东南西北全然不辨。

6 accurately   

adv.准确地，精确地

参考例句：

• It is hard to hit the ball accurately.准确地击中球很难。
• Now scientists can forecast the weather accurately.现在科学家们能准确地预报天气。