同学你好，该知识点来自沪江网校《英语零基础直达大学六级【双11专享班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
to do sth是不定式，往往可以表示还没有做某事，或者目的是做某事等，比如
Try to eat at least one piece of fruit a day.
努力做到每天至少要吃一个水果。

to be done是不定式的被动形式，表示被动含义，要被……
I had the good fortune to be selected
我有幸被选中。

done是动词的过去分词形式，过去分词的主要用法是：
1. 过去分词和be一起构成被动语态
I was beaten. 我被打了。

2. 过去分词和have/had构成完成时及各种相关变化。
I have been there. 我去过那儿。

3. 过去分词作状语、定语等，表示已经完成或者被动的动作。
the developed countries　发达国家
well-trained policemen　训练有素的警察


doing sth这里doing可能是动名词或者动词的现在分词，如果是动名词，表示一件事，如果是现在分词，表示动作正在发生，比如
He doesn't like asking his parents for help.
他不愿向父母求助。(asking是动名词，asking his parents for help是一件事，“向父母求助”）
I like to see them enjoying themselves.
我就愿意看着他们玩得高兴。(enjoying是现在分词，enjoying themselves是正在发生的事情）

being done 表示正在被……
I always had the feeling we were being watched.
我总感觉我们被监视了。

do sth常用于一般现在时，表示做某事，比如
He likes dogs. 他喜欢狗。

to have done sth是不定式的完成式，表示该动作已经发生过了，比谓语动作发生的早。
They seem to have lost their desire for life.
他们似乎已丧失了对生活的热望。（to have lost这个动作发生在seem之前）

to been done没有这种形式。

having done可能是现在分词的完成式或者动名词的完成式，表示比谓语动词更早的动作，比如
Having spent most of his adult life in England, he became a British citizen in 1938.
他在英国度过了他的成年生活的大部分时间，于1938年成了一个英国公民。(spend发生的比become早。)

having been done比having done多表达了一层被动的含义，被……
Having been told by his doctor that he was overweight, he's eating all the fibre and fruit he can.
被医生告知超重后，他一直拼命地吃高纤维食物和水果。

祝同学学习进步~