prep (1) (表示对象)为……(be given or sent to)：a parcel/letter/present～him 给他的包裹/信/礼物;leave a note/save a glass of water～Mary 给玛丽留一张便条/省一杯水;buy some chairs/the equipment～the office 给办公室买一些椅子/这种设备;

(2) (表示目的或作用)为了……(having a particular purpose)：an instrument～measuring speed 测量速度的仪器;a thermometer～measuring temperature 测温度的温度计;cupboards～toys 放玩具的小橱;closets～dishes 放盘子的碗橱;chairs～visitors 来宾座席;books～children 儿童读物; go to France～a holiday 去法国度假;go to a friend for advice 向朋友求教;

(3) (目标，去向)去往(in order to go to or reach)：set off/leave/depart～home 动身/起程/动身回家;the train/passengers～London 开往伦敦的火车/去伦敦的乘客;

(4) 为得到(in order to get，have，be，etc) (一般在动词后)：search～treasure 寻宝;run ～one's life 逃命;study～a degree 念学位;ask one's parents～money 向父母要钱;ask a policeman for directions 向警察问路;

(5) 有益(助)于(suiting the purposes or needs of)：herbs～cancer 治疗癌症的草药;medicine～the aged 供老年人用的药品;fight～one's country 为祖国战斗;give sb some medicine～his fever 给某人一些治疗发烧的药;have an operation～a heart disease 为某人的心脏病做手术;a collection～the poor 为穷人募捐;

(6) 1) 替代(instead of;in place of)：go to the meeting/teach English/clean the classroom～one's friend 替朋友去开会/教英语/打扫教室;use a substitute～butter 用一种替代物替代黄油;use the artificial flowers～real one's 用假花替代真花; 2) 代表(on behalf of)：speak～all the staff members/the parliament 代表所有职员/议会的讲话;a reception～the ambassador 代表大使举行的招待会; 3) 表示……的意思(meaning)：“Carte” is the French word～card. Carte是法语词，意思是卡片。

(7) (表示等值或比例关系)每……(就……)(in consideration of or in return for (sth))：sell/buy a television～40 dollars 以40美元卖掉/买一台电视机;a kilo of tomatoes～two dollars 两美元一公斤的西红柿;one rotten apple～every three good ones 每三个苹果中就有一个烂苹果;

(8) 赞成，拥护(in favour of;on the side of)：be～or against the honest government/the proposal/the slogan 赞成还是反对诚实的政府/计划/口号;Who did you vote～? 你投票赞成谁?

(9) 对(关)于(introducing sb/sth/that one's thoughts or feelings are directed to;concerning)：be responsible～sb's safety 为某人的安全负责;be ready～the journey 准备好旅游;be sad～sb 为某人感到悲哀;have no ear～music 不懂音乐;have no eye～colour 没有辨别色彩的能力;have no love～hard work 不喜欢艰苦的工作;

(10) 由于，因为(by reason of;because of)：～this reason 由于这个原因;jump/shout/weep～joy 高兴得跳起来/喊起来/流泪;be famous～its scenery/its churches/its wine 以优美的风景/教堂/酒著名;be rewarded～hard work 因为工作努力而受到奖励;get a medal～bravery 因为勇敢而得到奖章;do sth～sb's sake 为了某人做某事;

(11) 就……而言;至于(in effect on the interests or circumstances of) (通常用在形容词后面)：not bad～one's health 某人的健康还不错;not tall～one's age 就年龄而言，不算高;The day is warm～April. 对4月份来说，这样的天气就算暖和的。There's a lot of rain～this time of year. 对于一年的这个季节来说，雨下得不少。pressed～time 时间很紧迫;

(12) 1) (时间)(距离)达，计(indicating a certain time or distance)：know sb/sit still/wait～a long time 认识某人/静静地坐了/等了好长时间;walk (drive)～three miles/a long way 走(驾驶)了三英里/好长距离;2) (表示约定的时间、场合)在 (at a stated time;on a certain occasion)：a date～one o'clock 约会定于1点钟;an appointment～Monday 约见定于周一;a reservation～Saturday morning 为周六早晨预订的;

(13) 表示目的或意图(showing purpose or design) 1) (常用于名词或代词前，后接动词不定式)：It's～everyone to know/you to decide. 这得让每个人知道/由你作决定。make way～the car to pass 给车让路;2) (用于名词后和名词、代词前，后接不定式)：There's no need～anyone to know. 不需要让任何人知道。3) (用于形容词后面、名词或代词前，后接不定式)：It's useful～us to absorb whatever experience. 吸取任何的经验对我们来说都是有益的。4) (用在too+形容词或形容词+enough后面，后接不定式)：The box is too heavy～you to carry. 那盒子太沉了，你搬不动。Is it easy enough～the children to read the book? 读这本书对孩子们来说是不是够容易的?5) (用在名词代词前，后接不定式)：letters～the boss to sign 让老板签字的信;It's～you to say what Mary is to do. 告诉玛丽要做什么事是你的职责。6) (用于more…than之后)：Nothing would please me more than～my son to get the scholarship in Oxford University. 没有什么比我孩子在牛津大学得到奖学金让我更高兴的。

be for it 大概要受罚(infml)：You've broken the window—now you are～it. 你把窗户打碎了，你要受罚。

for all 尽管，虽然：F～all his money，he didn't seem happy. 尽管他有钱，但他好像并不幸福。

conj 由于，因为(because)(不用于句首)(fml)：It must be late，～I have been here a long time. 一定很晚了，因为我在这儿已经呆了好长时间了。

【辨异】 1) for与at的区别见AT。2) for与as、because和since的区别见AS。