Unit4Lesson12課件北師大版英語八年級上冊

Unit4Lesson12

HealthyBonesHowmuchdoyouknowaboutyourbones?Howtokeepyourboneshealthy?人的骨頭，早在胎齡二月時就開始形成。此后不斷生長，女子到二十歲左右骨頭才停止生長，男子則長到二十五歲左右。人的骨骼，一般在十八歲左右長度就穩(wěn)定了，也就是說不會再長高了。但是，骨的密度還要繼續(xù)增加。四十歲后，骨的密度就開始顯示出下降的趨勢。下降的快慢，則要看人的體質(zhì)情況而定。一般是體力活動多或喜好運動的人緩慢些。成人骨頭共有206塊，分為頭顱骨、軀干骨、上肢骨、下肢骨四個部分。但兒童的骨頭要比大人多11～12塊，就是說有217～218塊。醫(yī)學(xué)書上說，初生嬰兒的骨頭竟多達305塊。人體最長的骨頭是股骨，即大腿骨，它通常占人體高度的27%左右，有記錄的最長腿骨為75.9厘米。而耳朵里的鐙骨是人體內(nèi)最小的骨頭，它只有0.25～0.43厘米長成年人骨的重量約為體重的1/5，剛出生的嬰兒骨重量大約只有體重的1/7。although,butconj.

although的意思是“盡管，雖然”，用來引導(dǎo)讓步狀語從句，在一般情況下可以和though互換，但though比較口語化，而although較為正式，另外although的語氣比though重。當although/though引導(dǎo)的從句放在句首時，主從句之間要用逗號隔開。but引導(dǎo)的從句多放在主句后。although&butAlthough/Thoughhewastired,hekeptonworking.雖然他已經(jīng)累了，但仍然繼續(xù)工作。HeoftenhelpsmewithmyEnglishalthoughheisquitebusy.盡管他相當忙，但是還常常幫我學(xué)英語。HisofficeisinNewYork,butheisoftenaway.

他的辦公室在紐約，但他經(jīng)常不在。注意：although和though引導(dǎo)的從句不能與but連用，但可以互換。如：Althoughwearepoor,wearestillhappy.=Wearepoor,butwearestillhappy.

我們雖然窮，但是活得很開心。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意為“雖然，盡管”，通常位于______。but意為“但是”，通常位于________。句首句中Theyarelight,butbonesarestrongenoughtosupportourweight.=Althoughtheyarelight,bonesarestrongenoughtosupportourweight.【注意】although與but不能同時用于一個句子中。Findmoresentencescontains“Althoughorbut”,andchangethemintoanotherforms.Bonesareimportantbecausetheyhelpusmovefreely.=Boneshelpusmovefreely,sotheyareimportant.because意為“因為”，表示______。so意為“因此，所以”，表示________。原因結(jié)果LookattheSentenceBuilder.【注意】because與so不能同時用于一個句子中。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