Section Ⅲ Grammar--复习被动语态

　　[语 境 自 主 领 悟]

先观察原句 后自主感悟 1.Today，carnival in Venice is celebrated for five days in February.

2.If they broke the laws，they were put into prison.

3.The party will be held in five days.

4.Two hundred trees have been planted since the man came here. 1.句1用了一般现在时的被动语态，其构成为"am/is/are＋过去分词"。

2.句2用了一般过去时的被动语态，其构成为"was/were＋过去分词"。

3.句3用了一般将来时的被动语态，其构成为"will/shall＋be＋过去分词"。

4.句4用了现在完成时的被动语态，其构成为"have/has＋been＋过去分词"。 　　[语 法 精 要 点 拨]

　　一、被动语态的基本时态变化

　　1．各种时态被动语态的构成

　　被动语态由助动词be和及物动词的过去分词构成。被动语态可用于各种时态，其时态变化通过助动词be的不同形式来体现。

时态 动词的被动形式 例句 一般现在时 am/is/are done English is taught in most schools. 一般过去时 was/were done The letter was typed on the computer. 一般将来时 shall/will be done The problem will be discussed tomorrow. 现在进行时 am/is/are being done The bridge is being built. 过去进行时 was/were being done At that time the desk was being repaired. 现在完成时 have/has been done The house has been built. 过去完成时 had been done They said that their work had been finished. 过去将来时 would be done He said the trees would be planted soon.