主动语态→被动语态：

1、找到该句宾语（必须是在谓语动词后的）,将它提到句子开头.

3、把原句的主语用by构成的介词短语带出,也可不加.eg：Ifinishedmyhomeworkyesterday.→Myhomeworkwasfinished(byme)yesterday.特殊形式：

1、部分Vi加上适当介词可当作Vt构成被动语态.eg：Parentslookaftertheirchildrencarefully.→Childrenwerelookedafter(byparents)carefully.2、联系动词没有被动语态.eg：Thewaterfeelswarm.3、在主动语态中一些省略to的动词不定式改为被动语态时需加上to.eg：Teachersoftenmakehimstandoutside.→Heisoftenmadetostandoutside(byteachers).

所谓改成被动语态的意思就是让句子中原来充当宾语的成分提出来做主语,然后把原来的谓语动词改成被动形式,即在原来动词前加相应的be动词,然后动词改成过去分词形式.

例如：主动语态：We（主） plant（谓） many trees（宾） along the road.

被动语态：Many trees（主,原句中的宾） are planted（谓,be+过去分词） along the road (by us（原句中的主,有时可以省略）).

一般来时主动改被动时原来句中的主语,即动作的发出者就可以省略了.

句子改为被动语态的方法是，陈述句中的宾语变为主语，谓语动词变为 be + done 的形式，主语变成 by + 宾格，其余成分按顺序写下就可以。

看例句:

I eat apples every day. Apples are eaten by me every day.

I ate three apples yesterday.

Three apples were eaten by me yesterday.

I will eat two apples tomorrow. Two apples will be eaten by me tomorrow.