七年级 Grammar语法.docxVIP

Grammar一、情态动词（Modal Verbs ）1、定义：情态动词表示说话人对所说动作的观点，如需要、可能、意愿、怀疑等。2、形态：在形式上，情态动词一般没有人称和数的变化，有的情态动词没有时态的变化，如must。3、用法：情态动词本身词义不完全，不能单独作谓语动词，必须和不带“to”的动词原形连用。即：情态动词+动词原形。情态动词一般有多个意义。4、疑否：情态动词的一般疑问句通常将其提到句首，否定式一般是在其后面加not构成。5、语调：情态动词的肯定式一般不重读。二、常见情态动词can 1)表示能力We can speak a little English. Her sister can play the violin.I can play badminton but l cant play volleyball.2)表许可：You can play basketball on weekends. We cant run in the hallways.3）表示请求Can you help me with my Chinese? Could you tell him to call me back? （这儿could比can更委婉-.）must表示“必须”Dont arrive late for class. We must be on time.You must read a book before you watch TV.have to 表示“不得不”，“必须”We have to be quiet in the library. She has to do her homework first when she gets home.have to表示“必须，，时与must意义很接近，有时可与must互换，例如：We have to／must follow the rules.但在以下方面有所不同：must通常表示的是说话人的主观看法，语气比较强烈，have to往往强调客需要，例如：I must go now. Its a little late and I have to go now.它们的否定式含义大不相同，mustnt表示“不准”、“禁止”，而dont have to 表示“不必”例如：You mustnt talk to your mother like that.You dont have to come if you dont want to.3）must一般只表示现在．没有人称和数的变化[而have to则可以用于不同的时态，有人称和数的变化，例如：I/We/You/They must do something about it.I have to finish my work today. She has to finish her work today. They had to get to the station before 5:00.IL 现在进行时(Present Progressive Tense )现在进行时表示现在（说话瞬间）正在进行或发生的动作。例如：The students are listening to the teacher.He is watching TV now.现在进行时也可表示当前一段时间内的活动或现阶段正在进行的动作。例如：We are working on a farm these days.Im reading a history book this month.2.现在进行时是由动词be(am/is/are）+动词-ing形式构成的。以动词work为例，现在进行时的肯定式、否定式、疑问式和简略答语如下：肯定式否定式I am working.He/She is working.We/You/they are working.I am not working.He/She is not working.We/You/they are not working.疑问式和简略答语Am I working?Yes, you are. No, you are not (arent).Are we working?Yes, we/you are.No, we/you are not (aren’t).Are you working?Yes, I am.No, I am not.Are you working?Yes, we are. No, we are not (arent).Is he/she working?Yes, he/she is. No, he/she is not(isnt)Are they working?Yes, they are.No, th