there is so much work to be done和I have so much work to do.不定式中到底什么时候有主动什么时候用被动.morning air is so good to beathe的原因.

there is so much work to be done和I have so much work to do.不定式中到底什么时候有主动什么时候用被动.morning air is so good to beathe的原因.
there is so much work to be done和I have so much work to do.
不定式中到底什么时候有主动什么时候用被动.
morning air is so good to beathe的原因.

there is so much work to be done和I have so much work to do.不定式中到底什么时候有主动什么时候用被动.morning air is so good to beathe的原因.
如果句子的主语不是不定式的逻辑主语,则不定式需用被动语态.*i am going to the post office ,for i have a letter to post.《主动语态》(我要到邮局去,因为我有信要寄.) （句子主语i是不定式to post的逻辑主语,是我去发信,故用主动语态） A:Li ming ,i am going to the post office ,i know you have an import letter to post B:thank you ,but i have no letters to be posted now.通过对话的上下文理解之所以用to be posted 是因为句子中不是不定式主语,不是“李明寄”,而是“我”,所以用被动.

主要看句子的意思，以人为主的基本都是主动，以物为主的都是被动。
这里的主语本身就是空气，所以是形容空气是很好闻的，在这里没有人。

主语为人时用主动。一般主语为物时用被动，有的物也是没有被动形式的
the morning air是物，但他没有被动形式，所以后面用to beathe

A work不可数名词 用is that I have got 修饰work，略去的话就是there is so much work to do.