语态分类
英语动词有两种语态.，主动语态和被动语态。主动语态表示主语是动作的执行者，被动语态表示主语是动作的承受者。如：
They will build a new bridge over the river. (主动)
A new bridge will be built over the river. (被动)
汉语中常用“被”、“给”、“由”、“受”等词用来表示被动，而英语用：
助动词be + 及物动词的过去分词构成。
一、被动语态含义
所谓“被动语态”，相当于中文中常说的“被……”、“由……”的句式，汉语中常用“被”、“给”、“由”、“受”等词用来表示被动，而英语用：
助动词be + 及物动词的过去分词构成。
二、被动语态的使用
一般地说，有下面几种情况：
(1) 当不知道或没有必要指出动作的执行者时，常用被动语态，这时往往不用by 短语。
The house is quite old. It was built in 1950. (这座房子太旧了。它是1950年建成的。)
(2)突出或强调动作的承受者，如果需要说出动作的执行者，用by 短语。
These records were made by John Denver.
(3)为了使语气婉转，避免提到是谁做的这件事。
The construction of the new lab must be completed by the end of next month. (新实验室必须在下个月底前完工。)
三、 被动语态的时态、人称和数的变化
主要体现在be的变化上，其形式与系动词be的变化形式完全一样。列表如下：
一般现在时：am / is / are + done We are given a lot of homework to do.
一般过去时：was / were + done His desk was cleaned just now.
一般将来时：(A) will / shall + be + 动词的过去分词Some new factories will be built in our city this year.
(B) am / is / are + going to be +动词的过去分词. Your watch is going to be mended in an hour.
一般过去将来时：（1）.would / should + be + 动词的过去分词She said that some new factories would be built soon in our city.
(2).was / were +going to be + 动词的过去分词.He thought that your watch was going to be mended after an hour.
现在进行时：am / is / are + being + done I think we are being followed.
过去进行时：was / were + being + done The road was being mended.
现在完成时：have / has + been + done Someone has told me the sports meeting might be put off.
过去完成时：had + been + done When I got to the theatre, I found the tickets had already been sold out.
将来完成时：shall / will + have been + done
过去将来完成时：should / would + have been + done
［注］被动语态没有将来进行时和过去将来进行时。
四、含有情态动词的被动语态是由“情态动词（can/may/must ）+ be+ 及物动词的过去分词”构成。
He can not be found. / I must be paid for this.
五、主动语态变被动语态
1.把主动语态的宾语变成被动语态的主语。
2.把主动语态的谓语变成被动语态的be + 过去分词，时态要与原句保持一致。
3.把主动语态的主语变为介词by 的宾语，放在被动语态里谓语动词之后，by 短语可以省略。如果原句主语是地点名词，在被动语态中用in + 地点名词作状语。
（1） My aunt invited me to her dinner party.→ I was invited (by my aunt ) to her dinner party.
主语 谓语 宾语 主语 谓语 宾语
主动语态：人们说英语。People speak English in many countries.
被动语态：英语被说。 English is spoken in many countries..
