【高一 拓展阅读-生命科学】What Makes Hair Turn Gray

WhatMakesHairTurnGrayHaveyourparentsevertoldyouthatyou'recausingtheirhairtoturngray?Thegoodnewsisyou'renottheonlyreason.Thebadnewsis,theirhairisstillgoingtoturngrayoneday.Yourhairismadeupofafewdifferentparts.theshaftisthecolouredpartofhairyouseeonyourhead.Therootisthepartofhairthatattachestoyourhead.Eachroothasafollicle（毛囊）attachedtoit.Thisiswhereyourhairgetsitscolour.Whenhairturnsgray,itisbecauseitislosingpigment.Allhairactuallystartsoutwhite.Itturnscolourwiththehelpofapigmentcalledmelanin.Thewaythemelaninisdistributedthroughoutthehairhelpsdetermineyourindividualhaircolour.Somepeoplehavemoredarkmelanin,calledeumelanin（真黑素）.Othershavemoreredmelanincalledphaeomelanin（棕黑素）.Peoplewithblondehairhaveamixofbotheumelaninandphaemelanin.Thesecreatealightercolourofhairwhenmixed.Themelaninisplacedatthehairfolliclesandhelpscolourthehairthere.Aspeoplegetolder,theirbodiesstopprovidingasmuchmelanin.Asaresult,theirhairstartstoturngrayorevenwhite.Forsomepeople,thishappensallatonce,whileotherswillseetheirhairgraduallychangecolourovertime.Genescanhelpdeterminewhenaperson'shairwillgogray.Forexample,ifyourdadstartedgettinggrayhairatanearlyage,chancesareyouwillstarttogograyatanearlyagetoo.Factorssuchaspollution,theclimate,andchemicalexposurecanalsohelpcausehairtoturngrayfaster.Somepeoplealsosaystressmakesgrayhairappearfaster.Whilestressitselfdoesn'tcausegrayhair,thehormonesconnectedtostresscan.ReadingComprehensionChoosethecorrectanswerforeachquestion.1.Wheredoesyourhairgetitscolour?A.Fromtheshaft.B.Fromtheroot.C.Fromthefollicle.D.Noneoftheabove.2.Whatcolourdoeshairstartoutaccordingtothepassage?AGray.B.White.C.Black.D.Blonde.3.People'shairturnsgraydueto________.A.geneticdefects.B.theirnaughtychildren.C.aninsufficientsupplyofmelanin.D.greatstressfromwork.4.Whatisthebestwaytotellwhenyourhairwillturngray?A.Lookituponachart.B.Lookattheconditionofyourhairroots.C.Lookatotherfamilymembers.D.Lookathowmuchstressyouhave.5.Thefollowingfactorsalsohelpcausehairtoturngrayfasterexcept_______.A.pollution.B.theclimate.C.socialconnections.Dchemicalexposure.Vocabulary基础词attachv.系；贴；附加；连接；喜欢，依恋英tofastenorjoinonethingtoanother记词根记忆：at（表加强）+ach（钉）牢牢钉上→系；贴例You'dbetterattachaphototoyourapplicationform.你最好在申请表上附上照片。mixv.混合；调配n.混合；混合配料搭mixup弄乱；混淆createvt.创造；发明；创作英tomakesth.happenorexist记词根记忆：cre（产生）+ate（使…）→使产生→创造例Thegovernmentplanstocreatemorejobopportunitiesforyoungpeople.政府计划为年轻人创造更多的工作机会。happenv.（偶然）发生；碰巧英totakeplace，especiallywithoutbeingplanned例Theyhappenedtomeetthewriterofthenovel.他们碰巧遇见了这部小说的作者。changev.改变；更换；兑换n.零钱；变化英tobecomedifferent搭changesth.withsb.和某人交换某物change…into…将…变成…；兑换（货币）pollutionn.污染；弄脏记联想记忆：想方设法（solution），治理污染（pollution）搭noisepollution噪声污染connectv.连接；把…联系起来记词根记忆：con+nect（连接）连接搭connectAto/withB把A和B联系/连接起来Vocabulary进阶词shaftn.轴；柄，杆；矛杆；（光的）一束；（电梯的）升降机井记联想记忆：变速杆（shaft）用来改变（shif）速度pigmentn.颜料；色素英asubstancethatexistsnaturallyinpeople，animalsandplantsandgivestheirskin，leaves，etcaparticularcolour搭redpigment红色颜料syntheticpigment合成颜料accessorypigment辅助色素specialpigment特殊的色素melaninn.黑色素英adarksubstanceintheskinandhairthatcausestheskintochangecolourinthesunslightdistributev.分发，分配；散布，分布；分销记词根记忆：dis（分开）++tribut（给予）+e→分开给予→分发，分配搭distribute…equally平均分配…distributeexpenses分配经graduallyadv.逐渐地，逐步地英slowly，overalongperiodoftimechemicaladj.化学的n.化学制品搭chemicalreaction化学反应chemicalage