作者：沈建林
被动语态中的"省、补、变、加、留"指学习被动语态时应注意的"省主语、补主语、变代词、加上to、保留by"这些关键内容。
"省主语"，指主动语态变被动语态时，如果主动句中的主语为泛指情况的we, they, people时，被动句中将by短语省略。如：
We speak English. →English is spoken.
"补主语"，指将字面未出现行为者的被动句改为主动句时，应适当地补上主语，如we, they, people, someone等。如：
A car is stolen. →Someone steals a car.
"变代词"，指主动句中的宾语是宾格人称代词时，改为被动句要将其变为主格人称代词。如：
We must send her to the hospital at once. →She must be sent to the hospital at once.
"加上to"，如果主动句中含不带to的不定式（作宾语的补足语），变该句为被动句时，不定式前的"to"应恢复使用。如：
We saw him leave the classroom. →He was seen to leave the classroom.
"保留by"，指下列被动句中by短语不省略的情况：
a. 当by短语不表示行为者，而表示使用的手段和方法时。如：
Most of the work will be done by the computers.
b. 强调by短语中的动作行为者时。如：
Macao was forced by Portuguese more than four hundred years ago.
特别提示：一般将来时的被动语态：shall / will be +p. p.
现在完成时的被动语态：have / has been + p. p.
现在进行时的被动语态：am / is / are + being + p. p.
过去将来时的被动语态：should / would be + p. p.
另外需特别注意的是英语中look, smell, feel, taste, sound等系动词和表示"起止"意义的动词begin, start, finish, stop等，主动形式可表被动意义。
考题回放：
1. -Did you go to Jack's birthday party?
-No, I______. (2004天津市)
A. am not invited B. wasn't invited
C. haven't invited D. didn't invite
2. I like this silk dress, and it ______ so soft and comfortable. (2004江西省)
A. is feeling B. feels C. has felt D. is felt
3. People use computers widely in the world. (改为同义句)
Computers ______ widely ______ in the world. (2002辽宁省)
4. 第四十七届世乒赛上个月在巴黎举行。中国乒乓球运动员赢得理所当然。
The 47th World Table Tennis Championship ______ ______ in Paris last month. The Chinese ping-pong players ______ ______ ______. (2003济南市)
5. We heard them sing Peking Opera in that theatre last Sunday. (改为被动语态)
They were heard______Peking Opera in that theatre last Sunday. (2004重庆市)