在这里,to是介词,to doing 是介宾结构.
以下内容抄至网络,
look forward to doing wth （盼望做……事情）.
I'm looking forward to seeing you soon.（我盼望着快些看到你）
go to doing sth,去做……事情,通常省略to.
We're going (to) camping soon（我们要去野炊）
1．动词+介词to+动名词
(1) admit to doing sth.承认做了某事
He admitted to breaking the window.
(2) apply to doing sth.适用于做某事
The technology is applied to creating more products.
(3) object to doing sth.反对做某事
He is object to doing that.
(4) see to doing sth.负责做某事
I'm seeing to taking care of the olds here.
(5) stick to doing sth.坚持做某事
Don't give up!Stick to hard working and you'll soon succeed.
(6) take to doing sth.喜欢上做某事,逐渐习惯做某事
He takes to going to school on foot.
2．动词+宾语+介词to+动名词
(1) apply oneself to doing sth.专心致力于做某事
(2) devote sth.to doing sth.把……献给做某事
(3) devote oneself to doing sth.献身于做某事
(4) limit sth.to doing sth.把……限制在做某事的范围内
(5) reduce sb.to doing sth.使某人沦为做某事
3．动词+名词+介词to+动名词
(1) give one’s life to doing sth.献身于做某事
(2) give one’s mind to doing sth.专心做某事
(3) have a dislike to doing sth.厌恶做某事
(4) have an eye to doing sth.注意做某事
(5) have an objection to doing sth.反对（反感）做某事
(6) pay attention to doing sth.注意做某事
(7) set one’s mind to doing sth.决心做某事
4．be+形容词+介词to+动名词
(1) be equal to doing sth.等于做某事,能胜任做某事
(2) be used to doing sth.习惯于做某事
(3) be opposed to doing sth.反对做某事
(4) be reduced to doing sth.使某人沦为做某事
(5) be devoted to doing sth.把时间（钱,精力等）献给做某事
(6) be limited to doing sth.把……限制在做某事的范围内
5．其他结构+介词to+动名词
(1) get down to doing sth.开始做某事,认真处理某事
(2) look forward to doing sth.盼望做某事
(3) What do you say to doing sth?你认为做某事如何?
tips:
大家都知道to do是动词不定式，to doing是介词后面跟动词ing形式。
那什么时候to是跟行为动词构成不定式，什么时候又是做介词呢？ 我想区别在于to前面那个动词是不是及物动词。
打个比方want是个及物动词，后面可直接跟宾语。宾语是物如want an apple，宾语是动作就要跟动词不定式want to do（许多动词也能接doing，如enjoy doing）。
如果to前面是不及物动词，大家都知道不及物动词要接宾语必须加上介词，如to，at等。介词后面要跟动作就必须是doing形式。所以to doing就是不及物动词+介词to+doing的形式。如adjust作适应之意时为不及物动词,后面接物比如：adjust to the dark适应黑暗，接动作那就等于把dark这个名词换成动名词了，如adjust to living in the dark.
其实只要to后面可以加sth的那变成动词时都是doing
be accustomed to do sth是经常做某事的意思，be accustomed to doing sth是习惯于做某事的意思。
做习惯解释的时候，可以直接接sth，但是做经常做某事的时候不能直接接sth，你自己去体会下。不可能说“我经常某事”吧，肯定要“我经常干某事”
