新人教版高中英语选修2Unit 5 First Aid-Discovering useful structures教学设计（最终版）

我正在大街上行走时，遇到了一位老朋友。(walking和谓语动词met同时发生)Having finished the letter, he went to post it.他写完信后就把它寄了出去。(having finished是先发生的，went是后发生的)2．现在分词的语态使用现在分词的主动式还是被动式，这主要取决于现在分词和句子主语之间的关系。句子的主语就是分词的逻辑主语。Having been shown around the factory, they were very happy.(现在分词的被动式)被领着参观了工厂后，他们很高兴。Having finished his homework, he went to bed.(现在分词的主动式)完成了作业后，他上床睡觉。Seeing nobody at home, he decided to leave them a note.看到没人在家，他决定给他们留个便条。Having been told for several times, he still couldn't understand the rules.虽然被告诉了好几次，他还是不明白规则。Having received his reply, she rang him up.收到他的回信后，她给他打了电话。Being talked to, you should look into the eyes of the person.和别人说话时，你应该看着对方的眼睛。Having been asked to work overtime that evening, I missed a wonderful film.由于那天晚上被要求加班，我错过了一场精彩的电影。八、动词­ing形式的否定形式及动词­ing形式的复合结构1．动词­ing形式的否定形式通常是在其前加not，带有逻辑主语时 not应放在逻辑主语和动词­ing形式之间。