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，在质量不计、底面积相等的甲、乙、丙三个容器中，装入相同质量

2、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：肯定式：There _+a/an 可数名词单数可数名词单数/不可数名词不可数名词There _+可数名词复数可数名词复数There _ a handsome man in the classroom.There _ an egg on his head.There _ some orange juice in the glass.There _ some lovely girls

3、 in the classroom.There is_There are _2.否定式：否定式：There be+not+主语主语+其他其他 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 3.一般疑一般疑问句：句：一般情况：将一般情况：将be 动词提前。动词提前。含情态动词（如：含情态动词（如：will）

4、，则将情态动词提前。），则将情态动词提前。There 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：注意：some疑疑问变any4.there be句型句型中中对数量数量进

5、行提行提问 _ 对可数名词复数进行提问。对可数名词复数进行提问。e.g.There are 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。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（先熟悉笔一下（先熟悉笔记+后做后做题 共共7分分钟）单选（7道）()1.There _ some books on the sofa.A.hasB.isC.haveD.are()2._ children a

6、re there in the park?There are twelve children in the park.A.How 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 birth

7、day party for you next week?Yes,_.A.there isB.willC.there beD.there 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 a

8、re four seasons in a year.（改为一般疑问句，并作肯定回答）_ _ _ _ in a year?Yes,_ _.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肯否疑问肯否疑问There be 就近原则就近原则There be 是个近视眼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。就近原则就近原则There be 是个近视眼是个近视眼There _ a desk and fifty-

9、five chairs in the classroom.A.are B.is There _ fifty-five chairs and a desk in the classroom.A.are B.is 选择正确的选择正确的be动词动词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。

10、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（共一下（共4分分钟）单选（4道）()1.Whats 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

11、table.A.There are B.There isC.There wasD.There were()4._ an orange and two apples in the basket.A.There are B.There isC.There wasD.There were易错点注意！易错点注意！1.过去去时 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的时态变化的时态变化2.将来将来时 There

12、_ an English party next Saturday.There _ a concert this Saturday.考点来了There be肯否疑问肯否疑问There be 就近原则就近原则there be和和have的区别的区别 He has some money.There is some money on the table.there be 表示表示存在存在，意为意为“某地某地/某时有某时有”经常与地点状语经常与地点状语或时间状语连用；或时间状语连用；There is a meeting every evening.There are some legs in the c

13、lassroom.have 表示表示拥有拥有，即，即“某人有某人有”I have a round face.Mr.Wu has a square face.用用there be或或have/has填空填空1.I _ a good father and a good mother.2._a Tia 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 buildi

14、ng?9.What does Mike_?10._any books in the bookcase?练习一下一下考点来了There be肯否疑问肯否疑问There be 就近原则就近原则there be和和have的区别的区别 Lets practice！练习一下！练习一下单选(10道)（共（共10分分钟）()1.Jack _ 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

15、?_ 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 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

16、_ 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.There are few _ in the fridgeLets go and buy some peas and cabbages Avegetables Bfruit Cmeat Deggs()8.Look！There are some _ on the floor Ach

17、ild 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 完成句子完成句子1.I have three 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 _ _

18、 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 时间状语从句什么是when引导的时间状语从句呢？用用when引导的一个句子来表示引导的一个句子来表示时间概念时间概念，则为时间状语从句。，则为时间状语从句。翻译为翻译为“当当.的的时候时候”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