A human hair consists mainly of a protein called Keratin. It also contains some moisture and the trace metals and minerals found in the rest of the body. 

    人類(lèi)的頭發(fā)主要由一種叫角朊的蛋白質(zhì)組成，并含有水分及在身體其他部分也可找到的微量金屬和礦物質(zhì)。 

    The only living part of hair is underneath the scalp--when the hair had grown through the scalp it is dead tissue. 

    頭發(fā)唯一有生命的部分是在頭皮下面，當(dāng)它長(zhǎng)出頭皮時(shí)便成為無(wú)生命組織。 

    Hair’s natural shine is supplied by its own conditioner, sebum, an oil composed of waxes and fats and also containing a natural antiseptic that helps fight infection. Too much sebum results in greasy hair and conversely, too little sebum makes dry hair. 

    頭發(fā)的自然光澤來(lái)自它自身的護(hù)發(fā)素：油脂，它含有蠟和脂肪，還含有抗感染的自然抗菌劑。油脂含量過(guò)多會(huì)導(dǎo)致油性發(fā)質(zhì)，相反，油脂含量過(guò)少則會(huì)導(dǎo)致干性發(fā)質(zhì)。 

    Hair grows about 12 mm per month. If a person never has his hair cut, it would grow to a length of about 107 cm before falling out. Hair grows faster in the summer and during sleep. A single strand lives for up to seven years. 

    頭發(fā)每個(gè)月可長(zhǎng)12毫米，如果一個(gè)人從不剪發(fā)，頭發(fā)會(huì)長(zhǎng)至107厘米才開(kāi)始脫落。在夏天和睡覺(jué)的時(shí)候頭發(fā)生長(zhǎng)得較快。一根頭發(fā)的壽命可長(zhǎng)達(dá)7年。 
    
    Healthy hair is highly elastic and can stretch 20 or 30 per cent before snapping. A human hair is stronger than copper wire of the same thickness. A combined strength of a headful of human hair is capable of supporting a weight equivalent to that of 99 people. 

    健康的頭發(fā)非常富有彈性，可拉長(zhǎng)20％或30％而不斷。一根頭發(fā)比同等粗細(xì)的銅絲還要結(jié)實(shí)。滿頭頭發(fā)合在一起的力量可經(jīng)得起99個(gè)人的重量。 

    Scandinavians normally have thin, straight, baby-fine hair, and mid Europeans hair that is neither too fine nor too coarse. People native to the Indian subcontinent have coarse textured tresses while Middle Eastern populations have strong hair. The hair of Chinese and Japanese people is very straight; that of Latin-speaking and North African peoples can be very frizzy and thick. 

    斯堪的納維亞人的頭發(fā)又細(xì)又直，像嬰兒的頭發(fā)一樣；中部歐洲人的頭發(fā)不細(xì)不粗；印度次大陸人的頭發(fā)粗且打綹；中東人的頭發(fā)都很結(jié)實(shí)；中國(guó)人和日本人的頭發(fā)非常直順；而拉丁語(yǔ)國(guó)家及北非地區(qū)的人頭發(fā)卷曲而濃密。