被動語態（by+行為者）可省略
動作的行為者不分明，或不重要，或上下文中提到了行為者時，“by+行為者”可以省略。
1. The information is needed. 信息被需要。被誰需要不重要，所以省略行為者。
2. The book is being read. 書正在被讀。
3. The door was opened. 門被打開了。
練習
1. The door is opened (open).(被打開了)
2. The book is being read (read).(正讀着)
3. The computer has been used (use).(已經被用了)
4. The pencil has been sharpened (sharpen).(已經被削尖了)
被動語態的疑問句
（1）被動語態的一般疑問句：助動詞+主語+（其他助動詞）+動詞過去分詞~？
1. Is the information needed by him ? —>肯定句：The information is needed by him.
Yes , it is . / No , it isn’t.
2. Has the computer been used by her ? ->肯定句：The computer has been used by her.
Yes , it has . / No , it hasn’t.
3. Will the room be cleaned? ->肯定句：The room will be cleaned.
Yes , it will . / No , it won’t.
總結：肯定句的被動語態變一般疑問句通常只需把be/情態/助動詞放在主語前就行。
（2）被動語態的特殊疑問句：疑問詞+助動詞+主語+(其他助動詞)+動詞過去分詞~？
1. The information is needed by them. 信息被他們需要。
What is needed by him ? 對主語進行提問：什么被他們需要？
2. The girl is taken to Shanghai.. 女孩被帶到上海。
Where is the girl taken ? 對地點進行提問：女孩被帶到哪里？
3. The book has been read three times. 書已經被讀了三遍。
How many times has the book been read ? 對次數進行提問：書已經被讀了幾遍？
總結：被動語態的特殊疑問句只是在被動語態的一般疑問句基礎上，在句首加多了一個特殊疑問詞。
練習
1. Is the book being read (read) by her ? 他正在讀那本書嗎？
2. Has the computer been used (use) by them ? 他們用過那台電腦嗎？
3. How often is the English class taken (take)？ 英語課多長時間上一次？