句型变换复习·主动语态变被动语态

句型变换复习·主动语态变被动语态

被动语态由“助动词+及物动词的过去分词”构成。不同时态的被动语态的差异主要体现在助动词be的变化上，同时助动词be还要在人称和数上与主语保持一致。在将主动语态变为被动语态时，可按以下三个步骤：a. 把主动语态的宾语变为被动语态的主语。b. 把谓语变成被动结构(be＋过去分词) ，并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。c. 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。在无须说明动作的执行者或只强调动作的承受者时，by短语可以省略。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.

含有双宾语的主动句改为被动句时，应将其中一个宾语改为被动结构的主语，另一个宾语仍保留在原处。一种情况是把间接宾语(指人)变为主语，直接宾语(指物)不变；另一种情况是把直接宾语(指物)变为主语，间接宾语(指人)不变，这时,间接宾语前通常加介词to，有时加for。例如

My father gave me a new book on my birthday.

→I was given a new book (by my father) on my birthday. (间接宾语作了主语)

→A new book was given to me (by my father) on my birthday. (直接宾语作了主语)

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，原来带to的情态动词变成被动语态后，to 仍要保留。例如

We can repair this watch in two days.

→This watch can be repaired in two days.

They should do it at once.

→It should be done at once.