英语听力文摘 English Digest 719 每日一个洋葱可以和医生说再见么？

Does An Onion A Day Keep The Doctor Away?

Have you ever wondered why your eyes water when you chop onions?

Like Tear Gas

Despite what you might think, the smell of onions is not what makes most people cry. You see, an onion gets it distinctive¹ taste from compounds that contain sulfur² atoms. When you slice an onion, you damage its cells, triggering a chemical reaction that converts these compounds into an acid that acts like tear gas.

At the same time, the byproducts of this reaction condense to form the molecules³ responsible for the onion’s pungent⁴ odor. In other words, the same chemical reaction that makes you weepy also releases the onion’s smell.

Garlic And Health Benefits

A similar thing happens when you chop garlic. When it’s still in bulb form, garlic doesn’t smell like much. It’s only when you mince⁵ or dice⁶ the garlic’s cells that a chemical reaction releases the smell we associate with garlic.

However, no one cries from slicing garlic. This is because the byproducts of the chemical reaction that takes place in garlic are different from the byproducts you get when you chop an onion.

Scientists suggest that the same chemical that gives garlic and onions their distinctive smell helps them fight off bacteria and fungus⁷ and parasites⁸. There might be something after all behind all those reports that garlic and onions are good for you.

每日一个洋葱可以和医生说再见么？

你有没有想过为什么切洋葱时眼睛会流泪？

像催泪瓦斯

不管你怎么想，洋葱的味道并不是让大多数人哭泣的原因。你看，洋葱从含有硫原子的化合物中获得独特的味道。当你切洋葱时，你会破坏洋葱的细胞，引发一种化学反应，将这些化合物转化为一种酸，这种酸起到催泪瓦斯的作用。

同时，这一反应的副产物凝结形成了洋葱刺鼻气味的分子。换句话说，让你流泪的化学反应也会释放洋葱的气味。

大蒜和健康益处

当你切碎大蒜时，也会发生类似的事情。当它还是球状时，大蒜闻起来不太香。只有当你将大蒜的细胞切碎或切丁时，化学反应才会释放出我们与大蒜相关的气味。

然而，没有人因为切大蒜而哭泣。这是因为大蒜中发生的化学反应的副产物与你切洋葱时得到的副产物不同。

科学家们认为，赋予大蒜和洋葱独特气味的化学物质有助于它们抵御细菌、真菌和寄生虫。在所有这些报道背后，大蒜和洋葱对你有好处。

1 distinctive   

adj.特别的，有特色的，与众不同的

参考例句：

• She has a very distinctive way of walking.她走路的样子与别人很不相同。
• This bird has several distinctive features.这个鸟具有几种突出的特征。

2 sulfur   

n.硫，硫磺（=sulphur）

参考例句：

• Sulfur emissions from steel mills become acid rain.炼钢厂排放出的硫形成了酸雨。
• Burning may produce sulfur oxides.燃烧可能会产生硫氧化物。

3 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。

4 pungent   

adj.（气味、味道）刺激性的，辛辣的；尖锐的

参考例句：

• The article is written in a pungent style.文章写得泼辣。
• Its pungent smell can choke terrorists and force them out of their hideouts.它的刺激性气味会令恐怖分子窒息，迫使他们从藏身地点逃脱出来。

5 mince   

n.切碎物；v.切碎，矫揉做作地说

参考例句：

• Would you like me to mince the meat for you?你要我替你把肉切碎吗？
• Don't mince matters,but speak plainly.不要含糊其词，有话就直说吧。

6 dice   

n.骰子；vt.把（食物）切成小方块，冒险

参考例句：

• They were playing dice.他们在玩掷骰子游戏。
• A dice is a cube.骰子是立方体。

7 fungus   

n.真菌，真菌类植物

参考例句：

• Mushrooms are a type of fungus.蘑菇是一种真菌。
• This fungus can just be detected by the unaided eye.这种真菌只用肉眼就能检查出。

8 parasites   

寄生物( parasite的名词复数 )； 靠他人为生的人； 诸虫

参考例句：

• These symptoms may be referable to virus infection rather than parasites. 这些症状也许是由病毒感染引起的，而与寄生虫无关。
• Kangaroos harbor a vast range of parasites. 袋鼠身上有各种各样的寄生虫。