How Much Do You Know about Teeth?

廣東中山市卓雅外國語學(xué)校 劉杰琳 編譯

Everybody hasteeth. We all know that teeth help us eat. But is that all about teeth? How much do you know about teeth?

每個(gè)人都有牙齒。我們都知道牙齒幫助我們吃東西。但是，這就是牙齒的全部嗎？你對牙齒又了解多少呢？

1. Why do you need to brush your teeth every day? Why is there tooth decay?

為什么需要每天刷牙？為什么會(huì)有蛀牙？

It is veryimportantto brush your teeth every day,otherwisesuchcavitieswill grow on your teeth. Cavities areholesthat grow in your teeth. If you do not brush your teeth often, there will be some smallfood residuesleft in thegapsbetween the teeth after eating.Bacteriause these residues as food, and they willincrease. Bacteria will produce something called “acid”, which cancorrode hardthings.Therefore, the foodremainingon the teeth will help the bacteria to growcontinuously, the hard teeth will be corrodedlittle by little,and the teeth willformsmall holes, which are cavities. A tooth with a hole is a tooth decay.

每天刷牙是非常重要的，否則牙齒上就會(huì)長出這樣的齲洞。齲洞，就是牙齒里長出來的洞。如果經(jīng)常不刷牙，吃東西以后，會(huì)有一些細(xì)小的食物殘?jiān)粼谘例X縫里。細(xì)菌拿這些殘?jiān)?dāng)食物，就會(huì)繁殖得越來越多了。細(xì)菌會(huì)制造一種叫“酸”的東西，它能腐蝕堅(jiān)硬的東西。所以殘留在牙齒上的食物就會(huì)幫助細(xì)菌不斷生長，堅(jiān)硬的牙齒就會(huì)一點(diǎn)一點(diǎn)地被腐蝕，牙齒就會(huì)形成一個(gè)一個(gè)小洞洞，這就是齲洞。有了洞洞的牙齒，就是蛀牙。

2. How do teeth work?

牙齒怎么工作？

There are differenttypesof teeth in our mouth. The front teeth are called front teeth, and the teeth next to the front teeth are pointed, calledfangs. Look at the teeth at the back.They aremolars. Put the food in the mouth, the front teeth like achiselwill cut off the food; thesharpteeth like anawlwill helptearthe foodapart; the molars like astone mortarwillgrindthe food so that when the food enters thestomach, we can get itnutrition.

我們嘴巴里有各種不同類型的牙齒，最前面的牙齒叫作門牙，門牙旁邊的牙齒是尖的，叫作尖牙?？纯茨切┪恢每亢蟮难例X，它們是磨牙。把食物放進(jìn)嘴里，像鑿子一樣的門牙會(huì)把食物切斷；像錐子一樣的尖牙會(huì)幫忙撕開食物；像石臼一樣的磨牙會(huì)把食物磨碎，這樣食物進(jìn)入肚子后，我們就可以得到營養(yǎng)。

3. How many teeth do we have?

我們有幾顆牙齒？

Wegenerallystart to growdeciduous teethfrom 6 months old, and we have 20 deciduous teeth when we grow to about 2 and a half years old. At the age of six or seven, they will fall one by one, and newpermanent teethwill grow.Adultswill have 28-32 permanent teeth. Everyone has only one chance to change permanent teeth.

我們一般從6 個(gè)月開始長乳牙，長到2 歲半左右共有20 顆乳牙。在六七歲時(shí)乳牙會(huì)一顆一顆掉落，再長出新的恒牙。成年人有28 ～32 顆恒牙。每個(gè)人都只有一次換恒牙的機(jī)會(huì)。

4. How to protect teeth?

怎么保護(hù)牙齒？

Brush your teeth! Toremovethe food residue left between the teeth, you need to brush your teeth. Also, don’t eat too many sweets.In this way, we will havehealthyteeth!

刷牙！要把留在牙縫里的食物殘?jiān)宄蓛?，就需要刷牙。另外，不要吃太多的甜食。這樣，我們就會(huì)有健康的牙齒啦！

Notes:

teethn.（tooth 的復(fù)數(shù)）牙齒

tooth decay蛀牙

importantadj.重要的

otherwiseadv.除非

cavityn.齲洞

holen.洞；空腔

food residue 食物殘?jiān)?/p>

gapn.縫隙

bacterian.細(xì)菌

increasev.增長；增加

acidn.酸

corrodev.侵蝕

hardadj.硬的

remainv.保留

continuouslyadv.不斷地

little by little 一點(diǎn)一點(diǎn)地

formv.形成

typen.類型

fangn.尖牙

molarn.磨牙

chiseln.鑿子

sharpadj.鋒利的

awln.錐子

tear … apart把……撕開

stone mortar 石臼

grindv.磨

stomachn.胃；肚子

nutritionn.營養(yǎng)

generallyadv.一般地

deciduous teeth 乳牙

permanent teeth 恒牙

adultn.成年人

protectv.保護(hù)

removev.移動(dòng)

in this way 這樣

healthyadj.健康的