日本高清色视频在线视频在,国产香蕉97碰碰视频碰碰看,丰满少妇av无码区,精品无码专区在线,久久无码专区免费看,四虎欧美精品永久地址99,亚洲色无码一区二区三区

首 頁(yè) | 新聞?dòng)⒄Z(yǔ) | 視聽英語(yǔ) | 翻譯園地 | 實(shí)用英語(yǔ) | 專欄作家 | 奧運(yùn)英語(yǔ) | 新詞新譯 | 書友天地 | 輕松英語(yǔ)  | 凈臉聯(lián)盟 | 英語(yǔ)論壇 | 少兒英語(yǔ)
您現(xiàn)在的位置: En_language tips > 輕松英語(yǔ) > 一問到底 Dec 26, 2005
 





  Why does hair turn gray?

   
  Gray hair
   
  Why does hair turn gray?
Hair goes gray because pigment cells in the hair base at the roots of the hair stop producing melanin.

It doesn't matter if you are fair-haired or dark-haired you have the same chances of getting gray hair. However, it is more noticeable in darker haired people.

Graying of the hair generally starts at the age of around 30 for males and 35 for females however since the onset of this phenomena varies greatly from person to person, age is not the most accurate indicator.

The graying of hair appears to be genetically determined but the connection isn't at all clear.

So for now, your hair turning gray is just one of those mysteries of science that we have yet to solve. But salt and pepper hair always did look distinguished.

 

note:

pigment: 色素
melanin: 黒色素

 

 

 

onset: 開始

 

 



salt and pepper: 黑白相間而呈灰色的

 
 
 
Copyright by chinadaily.com.cn. All rights reserved
版權(quán)聲明:未經(jīng)中國(guó)日?qǐng)?bào)網(wǎng)站許可,任何人不得復(fù)制本欄目?jī)?nèi)容。如需轉(zhuǎn)載請(qǐng)與本網(wǎng)站聯(lián)系。
None of this material may be used for any commercial or public use. Reproduction in whole or in part without permission is prohibited.
<strong id="xdwva"><div id="xdwva"></div></strong>
<label id="xdwva"></label>

<thead id="xdwva"></thead>
    <label id="xdwva"></label>

  1. 日本高清色视频在线视频在,国产香蕉97碰碰视频碰碰看,丰满少妇av无码区,精品无码专区在线,久久无码专区免费看,四虎欧美精品永久地址99,亚洲色无码一区二区三区