请教关于to do 主动表被动的语法问题，谢谢。

Question

请教关于to do 主动表被动的语法问题，谢谢。i have a lat of work to do.
the tasks were assigned to do.
the water is not fit to drink.
beauty is to fight for.
he is to blame.

一、to do 在这几个句子中做定语状语表语，他们的作用不相同，但逻辑宾语都是句子中的名词，是因为避免重复所以省略掉了逻辑宾语？

二、to do 主动表被动适合那些范围，比如 the boss asks the project to be finished in two weeks.可以写成asks the project to finish么？

三、
i have a lot of work to do.和i have a lot of work to be done有什么区别。

谢谢！

@正达美

Answer 1

一。本人一向不赞成动词不定式主动表被动的说法。主动就是主动，被动就是被动，关键是搞清楚不定式与其他词的逻辑关系。
i have a lat of work to do.因为动词不定式的逻辑主语是句子主语，所以不定式用主动形式。
the tasks were assigned to do.这是动词不定式的反射用法，不定式的逻辑宾语就是句子的主语。
the water is not fit to drink.同上
beauty is to fight for.同上
he is to blame.同上
以上属于动词不定式的用法范畴。
二。boss asks the project to be finished in two weeks.不可以写成asks the project to finish。因为不定式的逻辑主语不明确。所以这里不定式与所修饰词是单纯的被动关系，所以要用不定式的被动形式作宾补。
三、
i have a lot of work to do.和i have a lot of work to be done。前者不定式的逻辑主语是句子主语。即不定式的执行者是句子主语。后者不定式的逻辑主语不是句子主语，即不定式的执行者不是句子主语。