主動語態變被動語態的方法

1. 基本方法

將主動語態的賓語變為被動語態的主語，將主動謂語變為被動謂語(be+過去分詞)，將主動語態的主語變為by短語(在被動句中用作狀語)：

He stole our money.→Our money was stolen by him.

【注】(1)若不強調動詞執行者，被動語態中的by短語通常可以省略：

The house was built in 1978. 這座房子是1978年建的。

(2) 在轉變語態時，要注意保持兩種語態時態的一致性：

The students will study the problem.

→The problem will be studied by the students.

A friend of ours is repairing the roof.

→The roof is being repaired by a friend of ours.

2. 雙賓動詞的被動語態

雙賓動詞即指帶雙賓語的動詞，它們在變為被動語態時，有以下兩種情形值得注意：

(1) 有些雙賓動詞(如award, buy, give, leave, lend, offer, pay, show, teach, tell等)在變為被動語態時，既可把間接賓語(指人)變為被動語態的主語，而把直接賓語(指事物)保留下來(稱為保留賓語)，也可把直接賓語(指事物)變為被動語態的主語，而把間接賓語改為介詞to 或for引起的狀語(到底用to還是for，與所搭配的動詞有關)。比較：

He gave her some money. 他給她一些錢。

→ She was given some money. / Some money was given to her.

He bought her a watch. 他給她買了一快表。

→ A watch was bought for her. / She was bought a watch.

(2) 有些雙賓動詞(如bring, do, make, pass, sell, send, sing, write等)通常用直接賓語(指事物)作被動語態的主語，而將間接賓語用作保留賓語(其前根據情況用介詞to或for)：

Father made me a doll. → A doll was made for me.

He wrote her a letter. → A letter was written to her.

(3) 有些雙賓動詞(如answer, deny, envy, refuse, save, spare等)通常用間接賓語(指人)作被動語態的主語，而將直接賓語用作保留賓語：

He answered me that question. → I was answered that question by him.

3. 含有情態動詞的被動形式

若主動語態中謂語含有情態動詞，在相應的被動語態中通常應保留該情態動詞，其結構為“情態動詞+be(或be的適當時態形式)+過去分詞”：

Everyone must know this. →This must be known by everyone.

請看以下帶情態動詞被動句實例：

This can’t be done in a short time. 這不是短期內可以完成的。

She may have been sent to work elsewhere. 她可能被派到別處工作去了。

The door must have been locked by my wife. 門一定是我妻子鎖的。

The environment should be improved. 環境應當改善。

The second point needn’t be discussed today. 第二點今天不必討論。