初二物理 液体压强 异形容器问题

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 _ 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。 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：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 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。 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. has B. is C. have D. are( ) 2. _ children are there in the park? There are twelve children in the park. A. How many B. How much C. How number D. 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. is B. are C. was D. were ( ) 5. Will there be a birthday party for you next week? Yes, _. A. there is B. will C. there be D. there will( ) 6. There _ any food in the kitchen. A. isnt B. is C. are D. arent( ) 7. There _two cups of tea on the table. A. is B. are C. have D. 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, _ _.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 the 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 in your bedroom? There _ a computer, two chairs and a bookshelf in my room. A. are B. be C. has D. is( ) 2. _some toys and a book on the shelf. A. There are B. There is C. There was D. There were( ) 3. _ some milk and an egg on the table. A. There are B. There is C. There was D. There were( ) 4. _ an orange and two apples in the basket. A. There are B. There is C. There was D. There were 易错点注意！1. 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 be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 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 _ 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 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.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 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 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 _ _ 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