to和for可能有一些词组，这些是不能改的。然后to有“去”的意思，比如to do sth就是去做什么事的意思。而 for的最大区别就是有“为了”的意思，比如 i buy a gifts for you .当然，for也有“去的”意思，比如leave for就是离开去哪里的意思其实，我们（如果还是学生的话）只要记住一些词组，或结合好语境就差不多了。呵呵``建议你最好不懂去问老师！
prep.向；对；到…为止；比；到，达
介词 prep. 到；向；往
word that shows where someone or something is going,etc.
· We walked to town.
我们走路进城。
· He leads us from victory to victory.
他领导我们从胜利走向胜利。
· Point to the blackboard.
指着黑板。
· That road leads to Beijing.
那条路通向北京。
· The peach is rotten to the core.
这个桃子烂到核里了。
介词 prep. （表示接受者）给
word that shows who is receiving something
· Please give the book to me.
请把书给我。
· I gave the candy to Mary.
我把糖果给了玛丽。
介词 prep. （表示几点差几分）到；缺
word that shows how many minutes before the hour
· It's ten minutes to six.
六点差十分。
· They fought to the last.
他们战斗到底。
介词 prep. 远至；直到
as far as; until
· I shall stay to the end of June.
我会一直待到六月底。
· She read the book from the beginning to the end.
这本书她从头到尾全都看了。
介词 prep. （表示地点）在；到
word that shows where
· He tied the donkey to the tree.
他把驴拴在树上。
· Fasten it to the wall.
将它系到墙上。
介词 prep. （表示原因）为
word that shows why
· He came to help me.
他帮我的忙来了。
介词 prep. （表示变化）成为
word that shows a change
· He was brought to poverty.
他变穷了。
· The sky changed from blue to grey.
天空由蓝变灰。
介词 prep. 表示发展到的地步
(expressing some point reached or extent)
· He is an Englishman to core.
他是彻头彻尾标准的英国人。
· I got wet to the skin.
我全湿透了。
介词 prep. 表示比较、相比
(expressing comparison) compared with�
· He is quite rich to what he once was.
比起从前，他现在是富裕多了。
介词 prep. 表示加上、附合、配合
expressing addition or accompaniment with
· Add three to five.
五加上三。
· We danced to the music.
我们配合着音乐跳舞。�
介词 prep. 表示结果或事情引发的情状
expressing a result or a resulting condition
· He tore it to pieces.
他把它撕成一片片。
· The train slowed to a stop.
火车缓速而后停下来。�
介词 prep. 构成动词不定式 用作名词；用作形容词；用作副词；其他用法
(used as a sign of the infinitive) a) noun use; b) adjectival use ;c) adverbial use;d) other uses
· a)It is wrong to tell a lie.
说谎是不对的。
· b)I have something to eat.
我有些吃的东西。
· water to drink
可饮用的水
· a house to let
出租的房子
· c)We eat to live.
我们吃是为了活下去。
· I am glad to see you.
见到你很高兴。
· d)To tell the truth, he is a good student.
说实话，他是一个好学生。
· He is to come at three o'clock.
他三点钟要来。
· He seems to be happy.
她看来似乎快乐。
· They learned how to write letters in English.
他们学习了怎样写英文信。
副词 adv. 来回地
to and fro, backwards and forwards
· She swung to and fro on the swing.
她在秋千上摆来摆去。
for:
prep.为；代替；因为；至于，对于；往 conj. 由于，因为
介词 prep. （表示时间、距离）计，达
word that shows how far or how long
· I have waited for three hours.
我等了三小时。
· For much of the time he suffered from bad health.
在很长时间里，他身体都不好。
· They were silent for a while.
他们沉默了一会儿。
· It's time for little girls to be in bed.
小女孩就寝的时间到了。
· We walked(for) a mile and ran (for) a mile.
我们走了一英里，又跑了一英里。
介词 prep. 开往，向
word that shows where someone or something is going
· She left Tianjin for Beijing.
他离开天津上北京去了。
· Is this the train for Glasgow?
这是开往格拉斯哥的火车吗？
介词 prep. 给，与，适于
word that shows who will get or have something
· This is a present for you.
这是给你的礼物。
介词 prep. 当作
as; as being
· I took him for his brother.
我把他当作是他的兄弟。
介词 prep. 因为，由于
by reason of, on account of; because of
· We could not see for the fog.
因为有雾，我们看不见。
· They did not draw the conclusion for the following reason.
由于下述理由他们没有作出结论。
· He was punished for stealing.
他因偷窃而受惩处。
介词 prep. 就…而言
word that shows whom you are talking about
· It is dangerous for a small child to cross the road alone.
小孩子自己过马路危险。
· It's for you to decide.
这件事由你来决定。
· He is tall for his age.
他小小年纪，个子倒挺高。（就他的年纪来说，他的个子算是高的。）
介词 prep. 为了，供
word that shows why you are doing something
· It is very cold for October.
十月里这样的天气真是很冷。
· I have got some picture books for you to look at.
我有一些让你看的书。
· No house was big enough for him to live in.
没有那么大的房子可供他住。
· We work hard for socialism.
我们为社会主义努力工作。
介词 prep. （比赛或战斗时）代表，代，替
on the same side in a sport or fight
· They would run for the United States.
他们将代表美国去参加赛跑。
· Tim plays tennis for his school.
蒂姆代表学校参加网球赛。
介词 prep. 价格，交换
word that shows how much something is
· I want to change this for that.
我想用这个换那个。
· I paid two dollars for the book.
为这本书我付了两元钱。
· I gave 5 pounds for it.
我出五英镑买的。
介词 prep. 赞成，支持
word that shows you like an idea
· Are you for or against the proposal?
你是赞成这个建议还是反对这个建议？
· Some people were for the strike and others were against it.
有些人赞成罢工，另一些人反对。
连词 conj. 因为
because; on account of the fact that
· I am thirsty, for the sun is hot.
我由于天热而口渴。
· I missed the beginning of the play,for I was late.
我没有看到话剧的开头部分，因为我迟到了。
books for grown ups a gift for Mother's Day
a present for a good boy once for all
for the present for the sake of glory
for the sake of for the time being
for yards (miles,etc.) in search for
in for answer for
apologize for ask for sb. or sth.
buy sb.for call for
care for sb.or sth. change one thing for another
die for do ... for
do sth.for nothing express admiration for
feel fear for sb.'s safety fight (die,etc.) for one's country
get ready for head for
hunt for look for sb. or sth.
long for pay (amount of money) for sth.
praise for be prepared for
read for pleasure responsible for
sail (leave) for Shanghai (India) sell sth.for sth.
send (go) for a doctor search for
to shout for joy study for
take sb.'s word for it use for
wait for sb.or sth. work for one's living
as for be in for it
be out for word for word
for all for the best
for the better for certain
for ever for example
for fear that for good
for one thing for love
for love of for love or money
for my (his, her) sake
prep. 代替
as a replacement for in exchange for in place of in return for instead of
prep. 至于
as regards in proportion to proportionate to respecting with reference to with regard to
prep. 就···而论
contributive to for the sake of in the honour of in the interest of
prep. 经过（多少时间）
during through throughout
prep. 因为
adapted to appropriate to concerning fit to fitting for suited to
prep. ···的原因
because of by reason of caused by due to on account of resultant to
prep. 以···为目的
destined for for the purpose of in destination of in order to in quest of looking for seeking so as to become to towards with a view to with the goal of
conj. 因为
as because forasmuch as inasmuch as seeing that since whereas
prep. 喜欢
favourable to in favour of in support of supportive of with
prep. 反对
against
