一、引导目的状语从句 so that“以便，为了”，引导一个表示目的的状语从句，此时可与 in order that 换用；从句谓语中常用情态动词 may/might, can/could, should, would 等；主从句间连接紧凑，没有逗号相隔。例： My old father began to study computer at the age of sixty so that(= in order that) he might keep up with times. 父亲六十岁时才开始学习电脑，以便跟上时代。 I spend more time learning English every day so that(= in order that) I can make greater progress this year. 为了今年取得更大进步，我每天用了更多的时间学英语。 二、引导结果状语从句 so that“因此，所以”，引导一个表示结果的状语从句，此时不能与 in order that 换用；从句中谓语根据需要使用相应的时态，主从句间可有逗号相隔。本文开头所列举例句中的 so that 就是这种用法。又如： She had not planned her time well,so that she did not finish her homework on time.她没把时间计划好，所以没按时完成家庭作业。 Wang Lang did not work hard enough, so that she is out of work when she is still young.王浪工作不够努力，因此，年轻时就失业了。 三、辨别两种不同状语从句 1) 根据句子结构辨别 从句谓语中含有情态动词 may/ might,can/ could, should, would 等，这时 so that 引导的是一个目的状语从句；从句前面有逗号和主句相隔，此时 so that 引导的是一个结果状语从句。试对比以下两个例句： Yesterday morning Yang Cheng got up early so that she could catch the first bus.昨天早上杨成为了赶上早班车起床很早。 Yesterday morning Yang Cheng got up early, so that she caught the first bus.昨天早上杨成起床很早，因此，她赶上了早班车。 2) 根据主从句逻辑关系辨别 so that 引导目的状语从句，一般表示尚未完成的目的或意图，主句和从句之间是结果与目的关系；而 so that 引导的结果状语从句则是表示主句所导致的结果，主句和从句之间是原因与结果的关系。试比较： I tell my students my new telephone number so that they may call me when necessary.我把新的电话号码告诉学生以便必要时他们给我打个电话。 I told my students my new telephone number so that all of them called me when necessary.我把新的电话号码告诉了学生，因此，必要时他们都给我打了电话。 四、同其它结构转换 so that 引导目的状语从句时，可以与表目的的动词不定式 (not) to do …/so as(not)to do …/ in order (not) to do … 互换。但主从句主语须一致(句 ① ②)，否则不能转换(句 ③)。 ① We went to the airport so that we might meet Professor Yang there. → We went to the airport to meet Professor Yang there. → We went to the airport in order to meet Professor Yang there. → We went to the airport so as to meet Professor Yang there. ② They had to walk a long way to/ in order to/ so as to fetch some firewood. → They had to walk along way so that they might fetch some firewood. ③ Mr.Cheng turned up the recorder so that every student in the classroom couldhear clearly. (主从句主语不一致) So…that/such…that
such…that作“如此…以致”解，连接一个表示结果的状语从句。与so…that
意思相同，但用法不同。如：so…that这一结构中，so后边可加形容词或副词，而such后边要用名词（这个名词前面可以带形容词，也可以不带）。因此，such…that的句型结构可分以下三种：
1)such＋a(an)＋adj.＋单数可数名词＋that…clause
He is such a clever boy that everybody likes him.
他非常聪明，大家都非常喜欢他。
He was such an honest man that he was praised by the teacher.
他非常诚实，因而受到了老师的表扬。
2)such＋adj.＋复数可数名词＋that…clause
They are such interesting novels that I want to read them once again.
这些小说非常有趣，我想再读一遍。
3)such＋adj.＋不可数名词＋that…clause
He has made such great progress that the teachers are pleased with him.
他进步得很快，老师们对他感到很满意。
注意：如果such后边的名词前由many、much、few、little等词所修饰的话，则不用
such而用so。例如：
He had so many falls that he was black and blue all over.
他摔了很多跤，以致于全身上下青一块，紫一块的。
He had so little education that he was unfit for this job.
他所受教育很少，不适合做这个工作。
There were so many people in the street watching the fire that firefighters could not get close to
the building.
街上有那么多人观看大火，以致于消防队员无法接近大楼。
6.In fact, his English is one of these articles was so good that Engels wrote him a letter and
praised him for it.
事实上，在那些文章中有一篇他的英文写得很好，恩格斯曾写信赞扬他。
so…that也作“如此…以致”解，连接一个表示结果的状语从句。so…that与such…
that意思相同，但用法不同。现将so…that用法总结如下：
so＋adj.／adv.＋that…clause（so的后面跟形容词或副词）
He runs so fast that nobody can catch up with him.
他跑得非常快，没人能追上他。
Dr. Wang is so good that everybody loves and respects him. (=He is so good a doctor that
everybody loves and respects him. =He is such a good doctor that everybody loves and respects him.)
他是一位好医生，大家都尊敬并爱戴他。
so that与so ... that ...的用法在近几年来全国各省市的中考试题中出现率较高，一直是历年来中考试题的重要考点。下面结合近几年来的中考试题，将so that与so ... that ... 的用法归纳如下：
一、so that引导目的状语从句时，表示“以便；为了”，从句中常使用can /could /may /might /will /would /should等情态动词或助动词；引导结果状语从句时，从句中一般不用can和may等词，在so that前可以用逗号，意思是“因此;所以”。如：
1. The little boy saved every coin_________ __________he could buy his mother a present on Mother's day.(用所给的短语填空，每个短语只能用一次)(2003大连市) (答案为so that。)
2. She bought a digital camera online she would save a lot of time. (2003扬州市)A.so that B.as soon as C.no matter D.such that (答案为A。)
二、so＋形容词或副词＋that ...引导结果状语从句。
(一)so＋形容词或副词＋that ...引导的肯定的结果状语从句，意思是“如此……以致于……”。如：
3.―__________fine day it is today! ―Yes,the sunshine is__________beautiful that I'd like to go swimming in the sea. (2003青岛市) A. How, such B. What a, very C. How, so D. What a, so (答案为D。)
4.当球迷们看到贝克汉姆的时候，他们如此激动以致于大喊大叫。(根据中文意思完成句子，
每空一词。)(2003北京市海淀区)When the football fans saw Beckham, they got__________excited__________they cried out. (答案为so，that。)
(二)so＋形容词或副词＋that ...引导的否定的结果状语从句，意思是“如此……以致于不能……”。如：
5. The camera is __________expensive__________ I can't afford it. (单项选择)(2004年辽宁省) A. so, that B. such, that C. so, as to D. enough, that (答案为A。)
6. Miss Gao asked a question, but it was__________that nobody could answer it.(2001安徽省) A.very difficult B. too difficult C. difficult enough D. so difficult (答案为D。)
注意：当that引导的结果状语从句为肯定句时，so ... that ...可以与be ... enough to do转换；当从句为否定句时，可以与too ... to ... 或be not ... enough to do转换。如：
7. David was so careless that he didn't find the mistakes in his test paper. (变为简单句)(2003福州市) David was__________careless__________find the mistakes in his test paper.
8. A：The boy is so young that he can't look after himself. B：The boy is not__________to look after himself.(改写句子，使B句与A句意思相近)(2004年桂林市)(答案为old enough。)
so ... that ... 引导结果状语从句有时候可以与such ... that ...句型相互转换。如：
9. The stone is so heavy that I can't lift it up. It is__________a heavy stone__________I can't lift it up.(改写句子)(2003南京市) (答案为such, that。)
such that 应该是“使得”反方向的意思。或可译做“约束条件为”？
so...that...”句型的意思是“如此/这么……以致于……”，常引导结果状语从句，但“so...that...”是个爱“变脸”句型，你一不留意就会出错。“so...that...”句型及其转换也是中考的热点，现将其用法总结归纳如下，让我们一起来看看它是怎样变的吧。 一、 so... that...句型中的so是副词，常常用来修饰形容词或副词，常用句型为：主语+谓语+so+adj. / adv. + that从句。例如： 1. he is so young that she can't look after herself. 2. The boy ran so fast that I couldn't catch him. 3. He was so angry that he couldn't say a word. 二、 在“such... that...”句型中，such修饰名词，意思也是“如此……以致于……”但当名词前有many、much、(a) few、(a) little等词修饰时，句子中要用“so...that...”而不能用“such...that...”。例如： 1. He has so much money that he can buy what he wanted. 2. I've had so many falls that I have pains here and there. 3. There is little water in the glass that I can't drink any more. 三、 so与that也可连起来写，即变成：... so that ...(以便 / 为了……)，引导目的状语从句。例如： 1. I got up early so that I could catch the early bus. 2. Please open the window so that we can breathe fresh air. 3. You must go now so that you won't be late. 四、以“so...that”引导的结果状语从句可以转换成不定式的简单句，即可转换为“...enough to...”或“...too...to”句型，但这种转换必须符合下列条件： 1. 当主句和从句的主语一致，且that从句是肯定句时，可用“enough to do sth.”来转换。例如： The man is so strong that he can lift the heavy box.→ The man is strong enough to lift the heavy box. He was so clever that he can understand what I siad. → He was clever enough to understand what I siad. 2. 当主句和从句的主语不一致，且that从句是肯定句时，可以用“enough for sb. to do sth.”来替换，但须注意不定式的宾语要省略。例如： The question is so easy that I can work it out. → The question is easy enough for me to work out. The box is so light that he can carry it. → The box is light enough for him to carry. 3. 当主句和从句的主语一致，且that从句是否定句时，可以用“too...to”来替换。例如： The girl is so young that she can't dress herself. → The girl is too young to dress herself. I was so tired that I couldn't go on with the work. → I was too tired to go on with the work. 4. 当主句和从句的主语不一致，且that从句是否定时，如果要用“too...to...”替换“so...that...”，则用介词for引出动词不定式的逻辑主语，可以用“too...for sb. to do sth.”来替换，注意不定式的宾语要省略。 The bag is so heavy that she can't move it. → The bag is too heavy for her to move. It is so hot that we can't sleep. → It is too hot for us to sleep.
参考资料：
http://zhidao.baidu.com/question/57051198.html?si=1