【www.jianqiaoenglish.com--英语听力】
Let’s begin with a cleaning tip: If you have some tarnished or corroded brass that you want to clean, an old brass candlestick for example, you can use Coca-Cola, or any other cola soft drink, and that brass will come clean.有个去污点子：如果你想要清除铜锈，例如铜烛台，可以使用可口可乐或者其它可乐饮料，清洗后的烛台光亮如新。
How Does This Work?饮料是如何清洁的呢?
And if Cola is such an effective cleaner of corroded metal , what is it doing to the inside of your stomach?如果可乐能有效清洁金属锈斑，那么可乐对人体的胃会产生什么影响呢？
Cola cleans brass because it’s mildly acidic.可乐能清洁铜锈是因为可乐呈弱酸性。
Here’s what happens: When brass or another metal alloy becomes tarnished, this means that there has been a chemical reaction between the oxygen in the air and one of the metals in the alloy.铜或其它金属合金生锈是因为空气中的氧气和合金中的某种金属发生了化学反应。
Oxygen atoms combine with metal atoms to form what’s called an oxide, and this oxide is what makes the metal appear tarnished. Acids, like the weak acid present in your can of Coke, can react with oxides to effectively reverse the process of tarnishing. The acid dissolves the metal oxides that make the tarnish, leaving only shiny metal behind.氧原子结合了金属原子，形成所谓的氧化物。氧化物就是金属锈。而酸，比如可乐中的弱酸，和氧化物产生化学反应，能有效避免生锈。酸可以分解金属氧化物，化学反应后的金属锃亮。
Try It At Home!在家试验
You can try this at home, even if you don’t have a brass candlestick. Leave a tarnished old penny in a glass of cola overnight. In the morning it will be shiny and fresh.即便家里没有铜烛台，你可以做这样的试验：晚上，将一枚旧硬币丢进装有可乐的杯里。第二天早上，硬币就变得闪亮如新。
Your Stomach And Acid酸对人体胃的影响
If the acid in cola is so good at attacking tarnished metal, what might it do to your insides? Actually, your stomach already contains its own supply of acid which it uses to digest food.如果可乐能有效清洁金属锈斑，那么可乐对人体的内脏会产生什么影响呢？事实上，人体的胃里就有分泌的酸液来消化食物。
This stomach acid is a great deal stronger than the acid in a can of Coke. Indeed, stomach acid would be an even better tarnish remover than cola!胃酸的酸性比一听可乐还强。说真的，胃酸甚至比可乐更能除锈。
