时差N小时 可乐除铁锈（下）（在线收听）

Acids, like the weak acid present in your can of Coke, can react with oxides to effectively reverse the process of tarnishing.

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。

The acid dissolves the metal oxides that make the tarnish, leaving only shiny metal behind.

酸可以分解金属氧化物，化学反应后的金属锃亮。

You can try this at home, even if you don't have a brass candle stick.

即便家里没有铜烛台，你可以做这样的试验：

Leave a tarnished old penny in a glass of cola overnight.

晚上，将一枚旧硬币丢进装有可乐的杯里。

In the morning it will be shiny and fresh.

第二天早上，硬币就变得闪亮如新。

If the acid in cola is so good at attacking tarnished metal, what might it do to your insides?

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?

Actually, your stomach already contains its own supply of acid which it uses to digest food.

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.

胃酸的酸性比一听可乐还强。

Indeed, stomach acid would be an even better tarnish remover than cola!

说真的，胃酸甚至比可乐更能除锈。