Passive voice（被动态）主动态和被动态的区别：
主动态：描述执行该动作的主语被动态：焦点放在动作上时使用。执行该动作的人并不重要。主动： Marry cleaned the classroom.被动：The classroom was cleaned (by Marry).
形式
示例
肯定
主语 + Tobe + 动词 – 过去分词
A rose is sent to her every day.
否定
主语 + Tobe + NOT + 动词 – 过去分词
Tom wasn’t invited to the party. Tom was so sad.
疑问
Tobe + 主语 + 动词 – 过去分词?
Will it be done tomorrow?
有时态的被动态
主语
Tobe (变化形式)
动词 – 过去分词(PP)
一般现在时
主语
Am/ is/ are
动词 – pp
The room is cleaned every two days.
现在进行时
主语
Am/ is/ are + being
动词 – pp
The room is being cleaned now.
现在完成时
主语
Have/ has + been
动词 – pp
The room has been cleaned since Monday.
一般过去时
主语
Was/ were
动词 – pp
The room was cleaned yesterday.
过去进行时
主语
Was/ were + being
动词 – pp
The room was being cleaned this time last week.
过去完成时
主语
Had been
动词 – pp
The room had been cleaned before he came.
一般将来时 (WILL)
主语
Will be
动词 – pp
The room will be cleaned tomorrow.
一般将来时 (BE GOING TO)
主语
Am/ is/ are + going to + BE
动词 – pp
The room is going to be cleaned on Monday.
将来进行时
主语
Will be being
动词 – pp
The room will be being cleaned at 7 pm tonight.
将来完成时
主语
Will have been
动词 – pp
The room will have been cleaned before midnight.
情态动词:
Can/ could/ may/ might/ should/ must/ …
主语
Modal + be
动词 – pp
The room must be cleaned by Friday.