情态动词被动语态.ppt

被动语态,定义:表示主语是动作的承受者.构成:助动词be+及物动词的过去分词。助动词有人称、时态和数的变化。含有情态动词的被动语态：情态动词be及物动词的过去分词。用法：当我们不知道谁是动作的执行者，或者没有必要指出谁是动作的执行者，或者只强调动作的承受者时，要用被动语态。,1.规则动词的过去分词：,1)一般情况在动词原形后加-ed,watch-watched,2)以不发音e结尾的加-d,practice-practiced,3)以辅音加y结尾的，去y变i加-ed,study-studied,4)以重读闭音节结尾，末尾只有一个辅音字母，先双写该辅音字母，再加-ed,stop-stopped,2.不规则动词的过去分词：,am,is,are,been,have,has,had,do,done,write,written,go,gone,情态动词的被动语态,肯定句:主语+情态动词+be+动词过去分词否定句:主语+情态动词+not+be+动词过去分词疑问句:情态动词+主语+be+动词过去分词,Teenagers should be allowed to choose their own clothes.,Teenagers shouldnt be allowed to choose their own clothes.,Should teenagers be allowed to choose their own clothes?,Teenagers should be allowed to choose their own clothes.青少年应该被允许选择他们自己的服装。Students should not be allowed to have part-time jobs.学生们不应该允许做兼职工作。Can these books be taken out of the reading room?可以把这些书带出阅览室吗？When must the work be finished?这些工作必须什么时候完成？,Some books were bought(by us),主语 谓语动词主动语态 宾语,主语,We should buy some books.,Some books should be bought by us.,谓语动词被动语态的过去分词,介词+宾语,1.把原主动句中的宾语变为被动句的主语。,2.把动词should+do变为被动形式即should be+过去分词。,3.原主动句的主语如需要则放在by后面以它 的宾格形式出现（注代词的宾格），如不需要则可省略。,4.其它的成分（定语、状语）不变。,主变被的4个步骤,exercise,They should allow us to have part-time jobs._.We should allow children to spend time with their friends._.The teacher should allow Anna to finish the picture._.Parents should allow children to choose their own friends._.,