初二物理液体压强异形容器问题.ppt

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1、液体压强重难点之异形杯问题,产生原因：液体受到重力作用，并且具有流动性公式：P=gh,液体压强,好了，废话不多说,上图,如下图，在质量不计、底面积相等的甲、乙、丙三个容器中，装入相同高度的同种液体,液体对容器底部的压强P甲 P乙 P丙液体对容器底部的压力F甲F乙F丙容器对桌面的压强P甲P乙P丙容器对桌面的压力F甲F乙F丙,相同高度同种液体,=,=,=,=,如下图，在质量不计、底面积相等的甲、乙、丙三个容器中，装入相同质量的液体,液体对容器底部的压强P甲 P乙 P丙液体对容器底部的压力F甲F乙F丙容器对桌面的压强P甲P乙P丙容器对桌面的压力F甲F乙F丙,相同质量,=,=,=,=,如下图，在质量不

2、计、底面积相等的甲、乙、丙三个容器中，装入相同质量的不同液体并使液面在相同高度处,液体对容器底部的压强P甲 P乙 P丙液体对容器底部的压力F甲F乙F丙容器对桌面的压强P甲P乙P丙容器对桌面的压力F甲F乙F丙,相同高度相同质量不同液体,=,=,=,=,总结一下,先算压强，后算压力,1.肯定式：There _+a/an 可数名词单数/不可数名词There _+可数名词复数,There _ a handsome man in the classroom.There _ an egg on his head.There _ some orange juice in the glass.There _

3、some lovely girls in the classroom.,There is_There are _,2.否定式：There be+not+主语+其他 There _ a computer in my bedroom.=There is no computer in my bedroom.There _ any students in the classroom.=There are no students in the classroom.,not a/an=no,not any=no,3.一般疑问句：一般情况：将be 动词提前。含情态动词（如：will），则将情态动词提前。Th

4、ere is some milk in the glass.Is there any milk in the glass?杯子里有牛奶吗？肯定回答：Yes,there _.是的，有。否定回答：No,there _.不，没有。There will be a party tomorrow evening._there _ a party tomorrow evening?明晚将有一个派对吗？肯定回答：Yes,there _.是的，有。否定回答：No,there _.不，没有。,注意：some疑问变any,4.there be句型中对数量进行提问 _ 对可数名词复数进行提问。e.g.There ar

5、e five birds in the tree.树上有5只鸟。_ are there in the birds?_ 对不可数名词进行提问。e.g.There is a little water in the bottle._ is there in the bottle?,练习一下（先熟悉笔记+后做题 共7分钟）单选（7道）()1.There _ some books on the sofa.A.hasB.isC.haveD.are()2._ children are there in the park?There are twelve children in the park.A.How

6、many B.How muchC.How numberD.What many()3._ there any juice in your glass?No,_.A.Are;there arent B.Is;there isnt C.Are;there not D.Is;there not()4.There _ a big tree near my house last year.A.isB.areC.wasD.were,()5.Will there be a birthday party for you next week?Yes,_.A.there isB.willC.there beD.th

7、ere will()6.There _ any food in the kitchen.A.isntB.isC.areD.arent()7.There _two cups of tea on the table.A.is B.areC.haveD.has,完成句子1.There is some soup in the bowl.（改为否定句）(1)_ _ _ soup in the bowl.(2)_ _ _ soup in the bowl.2.There are four seasons in a year.（改为一般疑问句，并作肯定回答）_ _ _ _ in a year?Yes,_ _

8、.3.There are five people in Lilys family.（对划线部分进行提问）_ _ people _ _ in Lilys family?,考点来了,There be肯否疑问,There be 就近原则,There be 是个近视眼,若句子中有几个并列主语时，be动词的形式要与离其最近的一个主语在人称和数上保持一致。,就近原则,There be 是个近视眼,There _ a desk and fifty-five chairs in the classroom.A.are B.is,There _ fifty-five chairs and a desk in t

9、he classroom.A.are B.is,选择正确的be动词There _ an apple on the table.桌子上有一个苹果。There _ some water in the cup.杯子里有一些水。There _ five apples on the table.桌子上有五个苹果。There_ one boy and two girls in the classroom.教室里有一个男孩和两个女孩。There _ two girls and one boy in the classroom.教室里有两个女孩和一个男孩,练习一下（共4分钟）,单选（4道）()1.Whats

10、in your bedroom?There _ a computer,two chairs and a bookshelf in my room.A.areB.beC.hasD.is()2._some toys and a book on the shelf.A.There are B.There isC.There wasD.There were()3._ some milk and an egg on the table.A.There areB.There isC.There wasD.There were()4._ an orange and two apples in the bas

11、ket.A.There areB.There isC.There wasD.There were,易错点注意！,过去时 There _ a cinema in our city two years ago.两年前，我们城市有一家电影院。There _ many trees here five years ago.五年前，这里有很多树。,There be的时态变化,2.将来时 There _ an English party next Saturday.There _ a concert this Saturday.,考点来了,There be肯否疑问,There be 就近原则,there b

12、e和have的区别,He has some money.,There is some money on the table.,there be 表示存在，意为“某地/某时有”经常与地点状语或时间状语连用；There is a meeting every evening.There are some legs in the classroom.have 表示拥有，即“某人有”I have a round face.Mr.Wu has a square face.,用there be或have/has填空1.I _ a good father and a good mother.2._a Tia

13、on the desk.3.He _ an iPad.4._a basketball on the playground.5.She _ some dresses.6.They _ a nice garden.7.What do you_?8._a reading-room in the building?9.What does Mike_?10._any books in the bookcase?,练习一下,考点来了,There be肯否疑问,There be 就近原则,there be和have的区别,Lets practice！练习一下,单选(10道)（共10分钟）()1.Jack _

14、 a big schoolbag._ many pencils in it.A.has;There is B.have;There are C.has;There are D.have;There is()2.Are there any maps on the wall?_ A.There are some.B.Yes,there is.C.Yes,there is one.D.No,there are.()3.How many _ are there in the picture?A.woman B.women C.buy D.milk()4.There arent _ trees near

15、 the house.There is only one.A.any B.some C.many D.much()5.There _ two bowls of rice on the table.A.is B.have C.has D.are,()5.Are there _ houses near the river?Yes,there are_.A.some,some B.any,some C.any,any D.some,any()_ no coffee left yesterday.A.It being B.There being C.It was D.There was()7.Ther

16、e are few _ in the fridgeLets go and buy some peas and cabbages Avegetables Bfruit Cmeat Deggs()8.Look！There are some _ on the floor Achild Bwater Cboxes Dgirl()9There _ a football game in our school Ahas Bwill have Cwill be()10There is _ food hereWell have to buy some Aany Bsome Cno,完成句子1.I have th

17、ree crayons in my schoolbag.（用there be句型改写成同义句）_ _ _ _ in my schoolbag.2.His uncle has some new story-books.（改为一般疑问句）_ his uncle _ _ new story-books?3.There is a woman near the house.（变复数）There _ _ _ near the house.4.There are some buses near the hill.（变单数）There _ _ _ near the hill.,六、when引导的 时间状语从句

18、,什么是when引导的时间状语从句呢？,用when引导的一个句子来表示时间概念，则为时间状语从句。翻译为“当.的时候”I could swim when I was 7.当我7岁的时候，我就会游泳。My mother is cooking when I get home.当我到家的时候，我妈妈正在做饭。Jenny will come to China when she has time.当詹妮有时间的时候，她就会来中国.Will you meet Danny when he comes?当丹尼来的时候，你要见见他吗？,1.熟背笔记，整理笔记中题2.每天一阅读3.天天练必刷800there be句型部分 Day1 Day2 Day3 Day4 Day5,