Unit 4 My ClassroomKey Points (重点)1. Imperative Sentence （祈使句）2. The Plural forms of a countable noun （可数名词变复数）3. “There be” structure （ there be 结构 ）Imperative Sentence （祈使句 ）一.三种构成： 1. 动词原形+。 Eg: Close the door！ Open your book!Sit down! Clean the window! 为了表示礼貌，可以在句首或句末加 please. Eg: Please close the door!Close the door, please.2. Be+形容词 Eg: Be careful! 小心点！Be kind! 友好一点！Be polite! 礼貌一点！ Try: 耐心点！Be patient!3. Let sb do(动词原形） sth orLets do (动词原形） sth Eg: Let the boy close the door!Lets go to school! try: 我们去游泳吧！Lets go swimming!祈使句变为否定句 直接在句前+Dont. eg: Dont open the door!Dont close the window!Dont be late!Dont be careless!名词的复数形式 one door two windows three boys four girls five pens six rulers seven bags eight desks nine pencils ten books Conclusion：1时，后面的名词要用复数形式 ！名词单数变复数的规则变化 door - doors window - windowsgirl -girls books - books Conclusion： 一般的名词直接在后面+s. bus -buses watch -watches box -boxes dish -dishesConclusion： “以s, x, ch, sh”结尾的单词，在后面 +es3. boy -boys key -keysday -days monkey -monkeys Conclusion：元音字母(a, e, i, o, u) +y 结尾的单词，+s4. family - families city -citiesfactory(工厂）- factoriescountry （国家，乡村） -countries 以辅音字母（除a, e, i, o, u,外的字母) +y 结 尾的单词，先把 y变为 i，+es5. leaf(叶子）-leaves shelf(架子）-shelveswife （妻子）- wives knife（小刀）-knives Conclusion： 以“f, fe”结尾的单词，把 “f, fe”变为 v+es6. photo(照片)-photos radio(收音机)-radiospotato(土豆)-potatoes tomato(番茄) tomatoesConclusion：以“o”结尾的，有生命的+es,无生命的 +sHave a try!two girl three catfour boyfive dishsix deskseven cityeight busnine day ten photo eleven wife twelve potato thirteen box fourteen family fifteen leaf sixteen watch seventeen month eighteen tomato nineteen desk twenty chairThere be 结构 定义：表示。有。，一般后面+ 表示地点或范围的介词短语。 There is a picture on the wall. There is a cup of tea on the table. There are thirty-eight students in Class 4. There are five birds in the tree. There are six pears on the tree.is or are?There is an apple and two pears on the table. There are two pears and an apple on the table. There is a blackboard on the wall. There are sixteen girls in our class. conclusion: 用is 还是are，取决于靠近它的第 一名词的单复数，如果是单数则用is,如果是 复数，则用are，即就近原则！Have a go! There _ blackboard on the wall. There _ two glasses on the table. There _ 38 students in our class. There _ 75 teachers in our school. There _ a plane in the sky. There _ one rubbers and two pens in the pencil box. There _ five footballs on the playground. There _ twenty-eight boys in Class Four.