最新《食物在口腔里的变化》课件1.课件PPT.ppt 35页

'《食物在口腔里的变化》课件1. 口腔是食物消化的第一站食物在口腔中发生什么变化？ 观察方法：咬一口面包，对着镜子咀嚼5次，观察面包的变化；接着再一边咀嚼一边感觉面包发生的变化，咀嚼30次后用镜子观察面包的变化；最后吞下面包。1.面包发生了怎样的变化？2.是口腔里的什么使面包发生了变化？舌头、牙齿、唾液 jiù切断食物撕开食物磨碎食物牙齿的分类和作用扁扁的像柱子、圆形的尖尖的 牙齿在食物消化中的作用是什么？牙齿的作用：是切断、撕裂和磨碎食物门齿：切断食物犬齿:撕开食物臼齿：磨碎食物 口腔是食物进入体内的入口，也是食物消化的开始。我们一定要保护口腔，保护牙齿，可是有些人没有保护好牙齿形成了蛀牙。你知道蛀牙是怎么形成的吗？主要形成原因是牙菌斑。牙菌斑是牙齿表面的一层几乎无色的薄膜，含有造成龋齿的细菌。如果我们不认真刷牙牙齿被牙菌斑逐渐腐蚀，蛀牙在严重情况下，会导致牙齿的坏死和脱落。 坚持早晚正确刷牙定期检查选用适量的含氟牙膏使用保健牙刷健康的饮食少吃糖护牙五步曲 LanguagepointsLessons26-27 (be)atwar处于战争／交战状态TheUSAthendeclaredthatitwasatwarwiththatcountry.Whenhecameback,hefoundthathiscountrywasatwar. desertvt.抛弃，遗弃，脱离；（在需要的时候）失去adj./n.沙漠；荒无人烟的·Thehunterdesertedhisinjuredcomrades.Whenhehadtospeaktotheheadteacher,hiscouragesuddenlydesertedhim.Therestoftheterritoryismostlydesert.Hewaslivingonadesertisland. falltopieces垮台，崩溃，倒塌，解体AfterthedeathofNapoleon,hisempirebegantofalltopieces.Theoldbuildingfelltopiecesinthewar.Theydesertedtheirorganizationanditfelltopieces. last(for)＋一段时间．持续／延续一段时间Thefilmwilllast(for)threehours.Themeetinglastedtoolongforustositstill. laydown放下;铺;制订,规定laydownone’slife牺牲生命laydownone"sarms放下武器Theyoungmotherlaidthebabydowngentlyonthebed.Theguestlaiddownhisknifeandforkwithalookofcompletesatisfaction.Thesepricelimitsarelaiddownbythegovernment.Theconferencewilllaydownthepropermeasuresandmethods. veryfew＝onlyafew＝onlyaveryfew很少／极少quiteafew＝agoodfew＝many好些／相当多notafew＝many不少／相当多 waitingtobereplaced现在分词作伴随状语Shefinishedallherworkfeelingrelaxed.Hesatinachairreadingnewspapers. replace=taketheplaceofvt.代替、取代JohnwillreplaceBillintheteam.Cananythingreplaceamother"sloveandcare?Wehavereplacedslavelabourwith/bymachines.MrAwillreplaceMrBaspresident.A先生将代替B先生任总裁。 watchover查看，照看，负责；看守，监视等①Iamhisbestfriend,andIwillalwayswatchoverhim.②Theywerewatchedoverbythreepolicemen. protectsb./sth.from/against…保护某人／某物免受…Youshouldwearyoursunglassestoprotectyoureyesagainst/fromsunlight.Theairconditioneriscoveredwithapieceofmetalboard,whichprotectsitfromwater. besidesadv.(＝moreover＝inaddition)还有，而且。通常置于句首。prep.除…之外，还有…Idon’twanttogooutnow.Besides,I’mfeelingtired.Thetaskisdifficult；besides,timeislimited.Therearefiveotherroomsbesidesthesetwo. tomakethingsworse插入语，情况更糟的是carryonwith＝goonwith＝continue(with) spreadvt.铺开，伸开；涂，抹；传播，散布等vi.伸展，延伸；蔓延，传染；传开①Hespreadablanketonthebed.②Thesea,blueandstill,wasspreadbeforeus.③Theradiospreadthenewsassoonasithappened.④Shespreadhertoysallovertheroom.①Theforestspreadsfromheretotheriver.②Intwentyyearsthecityhasspreadquicklytothenorth.③Thefirespreadfromthefactorytothehousesnearby.④Thecaptaintoldhismentospreadout. takeon开始具有，呈现，获得雇用，接受（从事），让上车Herfacetookonanangrylook.AfterthestudentsputupChristmasdecorations,theclassroomtookonaholidayappearance.Thefactoryhasopenedanditisbeginningtotakeonnewworkers.Hetakesonadditionalworkintheevenings.Thebustookonmorepassengers. nowhere置于句首是为了强调，这时句子多用倒装。如果nowhere不置于句首，则句子不倒装。Nowhereelsecanyouenjoysuchbeautifulmusic.Nowhereisthereaplaceforhimtosettledown.Mywatchisnowheretobefound.Theoldladywentnowhere,juststayedathome. 具有否定意义并放到句首形成倒装句的词除副词nowhere外，还有seldom,hardly,never,little,notonly…butalso,nosooner…than等。①OnlythendidIrealizethatIwaswrong.②Seldomdoeshetakepartintheconversation.③NeverinmylifehaveIheardofsuchafunnystory. oppositeadj.对面的；相反的oppositeto+n./pron.在……对面,和……相反oppositeprep.在……对面，有时和opposite(adj.)to意义相近 Heranacrosstotheoppositesideofthestreet.BillandMaryhadoppositeideasabouttheweather.Hesmiledandsatdownoppositetoher.Hispoliticalpositionisoppositetoours.Thehouseoppositeourswasburntdownlastweek.Thebusstoppedjustoppositethepostoffice. coveranareaof…=haveanareaof…占／有…的面积Chinahas/coversanareaofabout9,600,000squarekilometres. aswellas＝besides除…之外还othersoflessimportancewithinthisarea＝otherbuildingswhichwerelessimportantinthisarea. includevt.包括（有时有较活译法）①You"llfindthattheplanincludesmostofyoursuggestions.②TheChinesenationincludesthan50nationalminoritiesbesidestheHans.③Everyoneheretookpartinthefightagainsttheflood,includingoldpeople.④Everybodyhadsomethingtosay,meincluded. upuntil一直到……为止till/until作介词或连词,用于肯定句,谓语动词(或主句谓语动词)用持续性动词.HelivedinBeijingtill/until1990.PleasestayheretillIcomeback. ina…state或inastateof…处于…状态中Thehousewasinadirtystate.Heisinagoodstateofmind.他心情舒畅。Atthattime,thewholecountrywasinastateofwar. where,when,if,though等引起的从句，有时可以简化，只保留从句中必要的成分，特别当主谓语是itis/was时。Hemadesomemarksinthearticlewhere(itis)necessarytodoso.Let’spractisespeakingEnglishwhenandwhere(itis)possible.'