为什么要用被动语态表示句子的意思快说吧,我给你分

被动语态是个语法的范畴,是表示主语和动词之间语法和语义关系的动词形式.也就是说当主语是动作的承受者时,动词要用被动语态(Passive Voice).

用被动语态是强调动作的承受者,而主动是强调动作的发出者.其实用那个都可以,就看你要表达的意思了

因为你在陈述有些事情，动作的时候，不想，不用或没有必要，说明该动作是谁发出的

1强调动作接受者 eg.He was punished by his teacher because of cheating.
2没有特定的动作发生者 eg.He was killed in the murder.

英语中有主动和被动两种语态.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.只有及物动词才有被动语态.被动语态由“助动词+及物动词的过去分词”构成.被动语态的助动词同样有时态、人称和数的变化.
1.A new computer was bought to me by my father yesterday.
2.The children are looked after very well by Mrs Zhang.
3.He was seen to come into the meeting-room.(这里注意一下：由于see是感官动词,所以改为被动语态后要加to)
4.English is found very useful by us.
5.A lot of trees are planted by him.
后面的“by…”可加可不加,只要句子表示的是被动的意思就可以了.

就像中文一样，为什么要用被字句呢？