4、) 被动语态的用法 a. 不知道或没有必要说明动作的执行者是谁。 例如:Thedictionaryiswellkept. 字典被好好保存。(不知道电脑是谁偷的) This bridge was founded in 1981.这座桥竣工于1981年。 b. 强调动作的承受者,而不强调动作的执行者。 例如:Thesebookswerefoundinthe1920s。 (4) 主动语态变被动语态的方法 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
5、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 people. They make the bikes in the factory. The bikes are made by them in the factory. He cut down a tree. A tree was cut down by him. (5) 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+
6、be+过去分词”构成, 例如:My bike must be stolen. The work can’t be finished in two days. Step 2: Excise 1.Step 3: sum up make a conclusion about the passive tense Step 4: homework do the exercise about passive tense. 板书设计 “助动词be+及物动词的过去分词” 即be d