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基礎詞attachv.系；貼；附加；連接；喜歡，依戀英tofastenorjoinonethingtoanother記詞根記憶：at（表加強）+ach（釘）牢牢釘上→系；貼例You'dbetterattachaphototoyourapplicationform.你最好在申請表上附上照片。mixv.混合；調配n.混合；混合配料搭mixup弄亂；混淆createvt.創造；發明；創作英tomakesth.happenorexist記詞根記憶：cre（產生）+ate（使…）→使產生→創造例Thegovernmentplanstocreatemorejobopportunitiesforyoungpeople.政府計劃為年輕人創造更多的工作機會。happenv.（偶然）發生；碰巧英totakeplace，especiallywithoutbeingplanned例Theyhappenedtomeetthewriterofthenovel.他們碰巧遇見了這部小說的作者。changev.改變；更換；兌換n.零錢；變化英tobecomedifferent搭changesth.withsb.和某人交換某物change…into…將…變成…；兌換（貨幣）pollutionn.污染；弄臟記聯想記憶：想方設法（solution），治理污染（pollution）搭noisepollution噪聲污染connectv.連接；把…聯系起來記詞根記憶：con+nect（連接）連接搭connectAto/withB把A和B聯系/連接起來Vocabulary進階詞shaftn.軸；柄，桿；矛桿；（光的）一束；（電梯的）升降機井記聯想記憶：變速桿（shaft）用來改變（shif）速度pigmentn.顏料；色素英asubstancethatexistsnaturallyinpeople，animalsandplantsandgivestheirskin，leaves，etcaparticularcolour搭redpigment紅色顏料syntheticpigment合成顏料accessorypigment輔助色素specialpigment特殊的色素melaninn.黑色素英adarksubstanceintheskinandhairthatcausestheskintochangecolourinthesunslightdistributev.分發，分配；散布，分布；分銷記詞根記憶：dis（分開）++tribut（給予）+e→分開給予→分發，分配搭distribute…equally平均分配…distributeexpenses分配經graduallyadv.逐漸地，逐步地英slowly，overalongperiodoftimechemicaladj.化學的n.化學制品搭chemicalreaction化學反應chemicalage