Unit4Lesson12课件北师大版英语八年级上册

Unit4Lesson12

HealthyBonesHowmuchdoyouknowaboutyourbones?Howtokeepyourboneshealthy?人的骨头，早在胎龄二月时就开始形成。此后不断生长，女子到二十岁左右骨头才停止生长，男子则长到二十五岁左右。人的骨骼，一般在十八岁左右长度就稳定了，也就是说不会再长高了。但是，骨的密度还要继续增加。四十岁后，骨的密度就开始显示出下降的趋势。下降的快慢，则要看人的体质情况而定。一般是体力活动多或喜好运动的人缓慢些。成人骨头共有206块，分为头颅骨、躯干骨、上肢骨、下肢骨四个部分。但儿童的骨头要比大人多11～12块，就是说有217～218块。医学书上说，初生婴儿的骨头竟多达305块。人体最长的骨头是股骨，即大腿骨，它通常占人体高度的27%左右，有记录的最长腿骨为75.9厘米。而耳朵里的镫骨是人体内最小的骨头，它只有0.25～0.43厘米长成年人骨的重量约为体重的1/5，刚出生的婴儿骨重量大约只有体重的1/7。although,butconj.

although的意思是“尽管，虽然”，用来引导让步状语从句，在一般情况下可以和though互换，但though比较口语化，而although较为正式，另外although的语气比though重。当although/though引导的从句放在句首时，主从句之间要用逗号隔开。but引导的从句多放在主句后。although&butAlthough/Thoughhewastired,hekeptonworking.虽然他已经累了，但仍然继续工作。HeoftenhelpsmewithmyEnglishalthoughheisquitebusy.尽管他相当忙，但是还常常帮我学英语。HisofficeisinNewYork,butheisoftenaway.

他的办公室在纽约，但他经常不在。注意：although和though引导的从句不能与but连用，但可以互换。如：Althoughwearepoor,wearestillhappy.=Wearepoor,butwearestillhappy.

我们虽然穷，但是活得很开心。Choosethemainideaofeachpart.Part1(para.

)Part2(para.

)1-23-5A.Bonesarelightbutverystrong.C.Calciumcanmakebonessolid.B.Theintroductionofbones.D.Waystokeepboneshealthy.Readthefirstparagraphandanswerthreequestions.1.Whyarebonesimportant?2.Areourboneslight?3.Canbonessupportourweight?Becausetheysupportourbodiesandhelpusmovefreely.Yes,theyare.Yes,theycan.Whycanbonessupportourweight?Readthesecondparagraph,drawapictureofbonestructureandtakesomenotes.LookattheSentenceBuilder.Grammar1.Althoughtheyarelight,bonesarestrongenoughtosupportourweight.2.Bonesarehardontheoutside,buttheyaresoftontheinside.although意为“虽然，尽管”，通常位于______。but意为“但是”，通常位于________。句首句中Theyarelight,butbonesarestrongenoughtosupportourweight.=Althoughtheyarelight,bonesarestrongenoughtosupportourweight.【注意】although与but不能同时用于一个句子中。Findmoresentencescontains“Althoughorbut”,andchangethemintoanotherforms.Bonesareimportantbecausetheyhelpusmovefreely.=Boneshelpusmovefreely,sotheyareimportant.because意为“因为”，表示______。so意为“因此，所以”，表示________。原因结果LookattheSentenceBuilder.【注意】because与so不能同时用于一个句子中。Findmoresentencescontains“becauseorso”,andchangethemintoanotherforms.ontheoutsideontheinside

butbutlightstrongsofthard1.Whatareboneslike?Fillintheblanks.Bonesare…Paragraph2Althoughtheyareverylight,bonesarestrongenoughtosupportourweight.（para.1line7）

Everytimewewalk,sitdownorholdabook,weareusingourbones.Bonesareimportantbecausetheysupportourbodiesandhelpusmovefreely.Althoughtheyareverylight,bonesarestrongenoughtosupportourweight.2.Whyarebonesimportant?Paragraph1Bonesarehardontheoutside,buttheyaresoftontheinside.Thesoftpartofthebonemakesourblood.Bloodcarriesnutrientsthroughourbody.Italsohelpsmovewastematerialsawaysoourbodycanstayhealthy.2.Whyarebonesimportant?Paragraph2Becausetheysupportourbodiesandhelpusmovefreely.Andthesoftpartofthebonemakesourblood.Whyarebonesimportant?Bonesarehardontheoutside,buttheyaresoftontheinside.Thesoftpartofthebonemakesourblood.Bloodcarriesnutrientsthroughourbody.Italsoh