Unit 5 What are the shirts made of ? 一、核心语法-------被动语态(一)语态:英语的语态是通过动词形式的变化表现出来的。英语中有两种语态:主动语态和被动语态。 主动语态表示主语是动作的执行者。如:Many people speak Chinese. 谓语:speak的动作是由主语many people来执行的。被动语态表示主语是动作的承受者,即行为动作的对象。如:Chinese is spoken by many people. 主语English是动词speak的承受者。(二)被动语态的构成由“动词be+及物动词的过去分词”构成。人称、数和时态的变化是通过be的变化表现出来的。 一般现在时:am/is/are+done 一般过去时:was/were+done 一般将来时:will/shall be+done 现在进行时:am/is/are being+done 过去进行时:was/were being+done 现在完成时:have/has been+done(三)被动语态的用法 (1)不知道或没有必要说明动作的执行者是谁。 如:Some new computers were stolen last night. 一些新电脑在昨晚被盗了。 (2)强调动作的承受者,而不强调动作的执行者。 如:This book was written by him.这本书是他写的。 Your homework must be finished on time.你们的家庭必须及时完成。(四)主动语态变被动语态的法 (1)把主动语态的宾语变为被动语态的主语。 (2)把谓语变成被动结构(be+过去分词),根据被动语态句子里的主语的人称和数,以及原来主动语态句子中动词的时态来决定be的形式。 (3)把主动语态中的主语放在介词by之后作宾语,将主格改为宾格。例如: All the people laughed at him. → He was laughed at by all the people. He cut down a tree. → A tree was cut down by him.(五)含有情态动词的被动语态 含有情态动词的主动句变成被动句时,由“情态动词+be+过去分词”构成 We can repair this watch in two days.→This watch can be repaired in two days. They shou |