Unit2Robots第四学时　Grammar课件（人教版选修7）.ppt

英语·选修7（人教版）;第四学时　Grammar;Unit 2　Robots　　　 　　　　　 ;一、语态分类 英语动词有两种语态：主动语态和被动语态。主动语态表示主语是动作的执行者，被动语态表示主语是动作的承受者。 They will build a new bridge over the river. (主动) A new bridge will be built over the river. (被动) 汉语中常用“被”“给”“由”“受”等词来表示被动，而英语用“助动词be＋及物动词的过去分词”构成谓语动词的被动语态。 ;二、被动语态常用的八种时态 1．一般现在时。 The school doesn't allow us to enter the chemistry lab without a teacher. →We are not allowed to enter the chemistry lab without a teacher. 2．一般过去时。 They agreed on the building of a new car factory last month. →The building of a new car factory was_agreed_on last month. ; 3．一般将来时。 They will send cars abroad by sea. →Cars will_be_sent abroad by sea. 4．过去将来时。 The manager said they would complete the project by the end of the year. →The manager said the project would_be_completed by the end of the year. ; 语 法 精 讲;7．现在完成时。 Someone has told me the sports meet might be put off. →I have_been_told the sports meet might be put off. 8．过去完成时。 When I got to the theatre，I found they had already sold out the tickets. →When I got to the theatre，I found the tickets had already been_sold_out. ; 9．含有情态动词的被动语态。 含有情态动词的被动语态由“情态动词＋be＋及物动词的过去分词”构成。 You must hand in your compositions after class. →Your compositions must_be_handed_in after class.;三、被动语态的使用 1．当不知道或没有必要指出动作的执行者时，常用被动语态，这时可以省略by短语。 The cup with mixture was broken. 2．突出或强调动作的承受者，如果需要说出动作的执行者，用by 短语。 These records were made by John Denver. The cup was broken by Paul.; 语 法 精 讲; 语 法 精 讲; 语 法 精 讲; 3．在句型 sth. be＋adj.＋to do中用主动形式表被动意义。 The text is hard to understand. The box is heavy to carry. 4．在句型be worth doing中用主动形式表被动意义。 The book is worth reading a second time.