肯定结构: 1. Do型(即:动词原形(+宾语)+其它成分)。如:Please have a seat here. 请这边坐。 有的祈使句在意思明确的情况下,动词可省略。如:This way, please. = Go this way, please. 请这边走。 2. Be型(即:Be + 表语(名词或形容词)+其它成分)。如:Be a good boy! 要做一个好孩子! 3. Let型(即:Let + 宾语 + 动词原形 + 其它成分)。如:Let me help you. 让我来帮你。 否定结构: 1. Do型和Be型的否定式都是在句首加dont构成。如:Dont forget me! 不要忘记我! Dont be late for school! 上学不要迟到! 2. Let型的否定式有两种:“Dont + let + 宾语 + 动词原形 + 其它成分”和“Let + 宾语 + not + 动词原形 + 其它成分”。如:Dont let him go. / Let him not go. 别让他走。 3. 有些可用no开头,用来表示禁止性的祈使句。如:No smoking! 禁止吸烟!No fishing! 禁止钓鱼! 表示禁止时，尤其是标语等也可用“No+名词动名词”来表示。 No parking! No entry! No litter! Let后头除了是不带to的不定式动词 (The infinitive withoutto)之外，还可以是某些适当的副词，如out, in, down, alone等： (13) Let the puppy out. (14) Open the windows and let the fresh air in. 祈使句专项练习一、用括号内所给动词的适当形式填空。1. _ (not, be )late.2. _ (dust) the dressing table.3. _ (not, speak) with your mouth full of food.4. _ ( not, talk) and _ (read) a book.5. Open the window and _ (shut) the door.6. Lets _ (sweep) the floor.二、选择填空( )1 .The doctor says: “_ work so hard” A Stop B Dont C Cant D No( )2. _ in bed. Its bad for your eyes. A Not to read B Dont read C Dont to read D Not read( )3.Please _ look outside. Look at the blackboard. A not B dont C arent D cant( ) 4. The TV is too loud. Please_. A. turn it down B. to turn it down C. turn down it D. to turn down it( )5. Kate, _ your homework here tomorrow. A. bring B. brings C. to bring D. bringing( )6. _ me the truth, or Ill be angry. A. Telling B. To tell C. Told D. Tell( )7. _ careful! A.Be B. Being C. To be D. To ( )8. Dont _ in the river. A. swim B. swimming C. swam D. swims三、句型转换1. Will you please read it again more slowly? （改为祈使句）_ _ again more slowly, please.2. Please sit next to Nancy. （改为否定句）_ _ _ next to Nancy.3. Come to my house tomorrow. （改为否定句）_ come to my house tomorrow.4. Wear the glasses! （改为否定句）_ wear the glasses!5. Dont wash your hands!(改成肯定句)_ your hands!4 将以下祈使句改为否定式：1. Come here early. 2.Ask him. 3. Please wait for her. 4. Lets go there together. 可数名词不可数名词单数形式egg, policeman, animalair, water, music复数形式eggs, policemen, animals修饰语不定冠词（a,an），数词many,(a) few, several, a great number ofmuch, a little, a great deal ofSome, all, a lot of, lots of例句E.g. There are eight rooms in the house.He left for Beijing a few days ago.E.g. I am sorry to give you so much trouble.Do you have much money left?woman teacher-women teachers man teacher -men teachersMy family (be) a big one. All my family (be) in China now. news politicsmathsphysicsthermoschicken 小鸡 / 鸡肉room 房间 / 空间；位置work 作品/ 工作 paper 论文; 报纸/ 纸 glass 玻璃杯 / 玻璃 time 次；倍 / 时间 wood 树林 / 木头 fish 鱼 / 鱼肉 exercise 练习 / 运动；锻炼light 灯 / 光 fruit (各种)水果 / 水果需要记忆的特殊复数形式：manmen woman-women（例外：German-Germans） tooth-teeth foot-feetmouse-micechild-childrendeer-deer sheep-sheepChineseChinese JapaneseJapanese不可数怎样表示：借助表示“张”、“块”的单位词2.借助表示容量的词3.借助表示重量的词4.借助表示形状的词