【English】Passive Voice

英文動詞有主動語態 Active Voice 和被動語態 Passive Voice 
之分。

如果主語是動作或狀態的「發出者」，動詞就用主動語態；如果主語
是動作或狀態的「承受者」，動詞就用被動語態。
      
例如：
         
  1. John encouraged Mary.﹝約翰鼓勵瑪莉。﹞

  2. Mary was encouraged by John.﹝瑪莉受到約翰鼓勵。﹞      

※ 第一句的動詞 "encouraged" 是主動語態；第二句的動詞 

   "was encouraged"是被動語態。

動詞的被動語態的總形態是： 

    BE + 動詞的過去分詞

動詞由主動語態變為被動語態的步驟：

  1. 將賓語變為主語；

  2. 根據新主語的身和數，並考慮時態，然後決定 "BE" 的形態；

  3. 將舊主語放在 "by" 之後構成介詞短語。


1. Simple Present Tense

主動語態： I teach him.

被動語態： He is taught by me.


2. Present Continuous Tense

主動語態： I am teaching him.
         
被動語態： He is being taught by me.


3. Present Perfect Tense

主動語態： I have taught him.      

被動語態： He has been taught by me.


4. Present Perfect Continuous Tense

主動語態： I have been teaching him for a week.

被動語態： 缺


5. Simple Past Tense

主動語態： I taught him yesterday.

被動語態： He was taught by me yesterday.


6. Past Continuous Tense

主動語態： I was teaching him when you came.     

被動語態： He was being taught by me when you came.


7. Past Perfect Tense

主動語態： I had taught him before you came.

被動語態： He had been taught by me before you came.


8. Past Perfect Continuous Tense

主動語態： I had been teaching him an hour before you came. 

被動語態： 缺 


9. Simple Future Tense

主動語態： I shall teach him tomorrow.    

被動語態： He will be taught by me tomorrow.


10. Future Continuous Tense

主動語態： I shall be teaching him when you come.

被動語態： 缺


11. Future Perfect Tense

主動語態： I shall have taught him before the sun sets.

被動語態： He will have been taught by me before the sun sets.


12. Future Perfect Continuous Tense

主動語態： I shall have been teaching him for an hour before 
           the sun sets.

被動語態： 缺


其他例子

主動語態： I am looking for you.

被動語態： You are being looked for by me.

  * "look" 不及物動詞，加 "for" 成及物， "look for" 解作「找尋」。


主動語態： I sleep.﹝正確﹞

被動語態： I am slept.﹝錯誤﹞

  * 不及物動詞沒有被動語態。


主動語態： We must do it now.

被動語態： It must be done ( by us ) now.


※ 如果句子中有這類助動詞，那麼動詞的被動語態的形態是：

    助動詞 + BE + 動詞的過去分詞 

※ 在不引起誤解的情況下， "by us" 有時可省去。 

         
主動語態： You can do it now.

被動語態： It can be done by you now. 


主動語態： I gave him a book.

被動語態： He was given a book by me.


※ 如果有兩個賓語，通常代表人的間接賓語變為主語，另一個保留
   不動，稱為「保留賓語」Retained Object。

※ 不過，也可以把直接賓語變為主語。


主動語態： I gave him a book.

被動語態： A book was given him by me.

§ 使用被動語態的一般因由

1. 不易說出動作或狀態的「發出者」

例如：

  This building was completed in 1980.

  * 由誰建成，不易說出。

         
2. 不便說出動作或狀態的「發出者」

例如：

  The meeting has been postponed till Friday.


3. 動作或狀態的「承受者」比「發出者」更需強調

例如：

  A press conference was held last night.


4. 為了修辭

例如：

  The teacher loves the students and is loved by them.