【英语时差8,16】为何食盐中含有碘？

 Pure, ordinary salt is simple. The scientific name for it is sodium¹ chloride. But the label on a salt box shows that table salt usually contains more than just sodium chloride. Table salt often comes in “iodized” form — which means it includes a small amount of potassium iodide or sodium iodide. Iodized salt is intended to supply us with the trace amount we need of the chemical element iodine², which is necessary for the proper functioning of our thyroid gland³. An iodine-deficient diet leads to enlargement of the thyroid gland, a condition called goiter. Severe iodine deficiency during pregnancy⁴ is also dangerous to the child.

1 sodium   

n.（化）钠

参考例句：

• Out over the town the sodium lights were lit.在外面，全城的钠光灯都亮了。
• Common salt is a compound of sodium and chlorine.食盐是钠和氯的复合物。

2 iodine   

n.碘，碘酒

参考例句：

• The doctor painted iodine on the cut.医生在伤口上涂点碘酒。
• Iodine tends to localize in the thyroid.碘容易集于甲状腺。

3 gland   

n.腺体，(机)密封压盖，填料盖

参考例句：

• This is a snake's poison gland.这就是蛇的毒腺。
• Her mother has an underactive adrenal gland.她的母亲肾上腺机能不全。

4 pregnancy   

n.怀孕，怀孕期

参考例句：

• Early pregnancy is often accompanied by nausea.怀孕早期常有恶心的现象。
• Smoking during pregnancy increases the risk of miscarriage.怀孕期吸烟会增加流产的危险。