4、This book sells well.这本书畅销。

3、The watch looks good.这表看起来很好。

2、The flower smells sweet.这花闻起来很香。

1、An accident was happened yesterday.(×)昨天发生了一起事故。

　　 　An accident happened yesterday.

2、不及物动词sell, wash, read , write, open, close, shut, lock, wear等，常用主动形式表示被动意义。　

1、happen, take place, break out, belong to ,cost, take

　系动词无被动语态：以主动形式表示被动之意

常见的系动词有：

① be动词 　 ② ……起来(7个)：look/seem/appear, feel(感觉，摸起来), sound, smell, taste 　　 e.g. She seems/appears happy.　　　 It smells terrible.　

　 ③ (逐渐)变得/变成：become, grow, get, turn, come, go 　　 e.g. His wish has come true. 　　　　 People often went hungry in the old days. 　　　　 The tree is growing tall. 　 ④ 保持：keep, stay 　　 e.g. We must keep quiet in the reading room.

2、主动语态变为被动语态的注意事项：

　 含有双宾语，即直接宾语(常指事物)和间接宾语(常指人)的句子，每个宾语都可变为被动语态的主语，即其被动语态有两种形式。但多以间接宾语作主语。

　Jack told us the truth.杰克告诉了我们真相。

　We were told the truth by Jack.

　The truth was told (to) us by Jack.

　转换图示：

1、主动语态变为被动语态的步骤：

　(1)将主动句的宾语变为主语：

　注意：如果主动句的宾语是代词，需将其由宾格变为主格。如：

　Tom killed him. → He was killed by Tom.

　(2)将动词改为"be+过去分词"。

　注意：　

　They held a meeting yesterday. → A meeting was held by them yesterday.

　他们昨天开会了。

　(3)将主动语态的主语改为be…放在谓语动词后。

　注意：如果原主语是代词，则应由主格变为宾格。

　He sang a song. → A song was sung by him.

2、被动语态的句式变化：

　以一般现在时和动词invite为例，列表说明被动语态的句式变化：

　　3、含有情态动词的被动语态

　情态动词的被动语态结构为：情态动词+be+过去分词；其时态及句型的变化仅由情态动词完成，"be+过去分词"部分不变。如：

　Tables can be made of stone.桌子可由石头制造。

　Tables could be made of stone at that time. 那时桌子可由石头制造。(一般过去时)

　Can tables be made of stone? 桌子能用石头制造吗？(疑问句)