TO做介詞的用法：
1.(表示方向、目的地) 向
She went to the window and looked out.她走到窗前向外望去.
2.去 (參加)
He came to dinner.他來吃晚飯.
3.附著
There was a piece of cloth tied to the dog's collar.有一條布系在狗項(xiàng)圈上.
4.(表示方位) 在
Hemingway's studio is to the right.海明威的工作室在右邊.
5.給 [用法v+n+to+n]
He picked up the knife and gave it to me.他撿起刀并拿給我.
6.(表示行為或情感針對的目標(biāo)) 對于 [用法：adj/n+to+n]
Marcus has been really mean to me today.馬庫斯今天確實(shí)一直對我不友好.
7.對 (表示受某事影響) [用法：adj/n+to+n]
He is a witty man,and an inspiration to all of us.他是一個風(fēng)趣的男人,對我們所有的人是一種鼓舞.
8.對… (說)
I will explain to them that I can't pay them.我會向他們解釋說我無法付錢給他們.
9.(表示反應(yīng)或情感) 致使
To his surprise,the bedroom door was locked.使他吃驚的是,臥室的門是鎖著的.
10.在…看來
It was clear to me that he respected his boss.在我看來,顯然他尊重他的老板.
11.(表示狀態(tài)或形勢等的變化) 成為
The shouts changed to laughter.叫喊聲變成了笑聲.
to還有不做介詞的情況,比較少：
CONVENTION（習(xí)慣表達(dá)）：……（程度副詞之類的） to
If you say "There's nothing to it," "There's not much to it," or "That's all there is to it," you are emphasizing how simple you think something is.(表示強(qiáng)調(diào)) 容易得很 當(dāng)to后面接do原形的時候，是當(dāng)作不定式來用，當(dāng)后面接doing的時候，它是當(dāng)作介詞，一般to后面接的都是do原形，只有在少數(shù)的固定詞組，后者特殊用法中才當(dāng)作介詞接doing，比如get used to習(xí)慣于。。。。
如：I get used to getting up early我習(xí)慣早起，這里的to便是介詞另外，你是想從哪個角度去理解呢？我覺得你只知道大概就行了，要是從英語專業(yè)角度給你具體分析吧，那可以有好多呢那就簡單了，常見的一些你記住就可以了look forward to doing

say no to doing

pay attention to doing

prefer doing to doing

get used to doingcontribute to doing
devote to doing

commit to doing不客氣！感嘆句那個你看懂了沒有？哦，好的