英语中的构词法主要有三种，即转化法、合成法和派生法。
转换法在英语中，一个单词由一种词性转化为另一种或几种词性而词形不变的方法叫做转化法。
1. 动词转化为名词Let me have a try. 让我试试。
They are only allowed to sell soft drinks at school.在学校里只准许他们出售不含酒精的饮料。
2. 名词转化为动词He shouldered his way through the crowd. 他用肩膀推开人群前进。
The smell from the kitchen made his mouth water.从厨房传来的气味使他流口水。
3. 形容词转化为动词We will try our best to better our living conditions.我们要尽力改善我们的生活状况。
They tried to perfect the working conditions.他们努力改善工作条件。
4. 形容词转化为名词He didn’t know the difference between right and wrong.他不辨是非。
The old in our village are living a happy life.我们村的老年人过着幸福的生活。
5. 形容词转化为副词How long have you lived there? 你在那儿住多久了？6. 个别词在一定场合中可转化为名词Warm clothes are a must in the mountains.穿暖和的衣服到山区去是必须的。
Life is full of ups and downs.人生有得意时也有失意时。
His argument contains too many ifs and buts.他的辩论中含有太多的“如果”和“但是”。
合成法由两个或两个以上的单词连在一起合成一个新词，这种构词法叫做合成法，合成的词叫做合成词。
合成词一般看其词，知其意。
1. 合成名词名词/代词+名词 newspaper blood-test she-wolf动词+名词 typewriter pickpocket daybreak 形容词+名词greenhouse highway副词+名词overcoat outside名词+v.-ing/v.-ing +名词handwriting reading-room freezing-point 动词+副词/ 副词+ 动词 breakthrough get-together outbreak outcome 名词+介词+名词sister-in-law editor-in-chief2. 合成形容词名词+形容词/形容词+名词world-famous duty-free large-scale long- term 副词+形容词 over-anxious evergreen名词+过去分词 man-made sun-burnt名词+现在分词 peace-loving English-speaking形容词+现在分词good-looking easy-going副词+过去分词well-informed widespread副词+现在分词 hardworking far-reaching形容词+名词+ed warm-hearted absent-minded数词+名词+ed three-legged ten-storied数词+名词 one-way five–star数词+名词+形容词ten-year-old 800-meter-long名词+to+名词 face –to-face door - to -door3. 合成动词名词+动词baby-sit sleepwalk副词+动词 outnumber underestimate overwork形容词+动词 whitewash4. 合成副词形容词＋名词 meanwhile anyway形容词＋副词everywhere anyhow副词＋副词 however介词＋名词 beforehand overhead介词＋副词 forever5. 合成代词代词宾格＋self/selves herself themselves物主代词＋self/selves myself yourselves形容词＋名词anything nothing6. 合成介词副词＋名词inside outside介词＋副词without within副词＋介词into派生法由一个词加上前缀或后缀构成一个与原单词意义相近或截然相反的新词叫做派生法。
1. 前缀除少数前缀外，前缀一般改变单词的意义，但不改变单词的词性。
（1）表示否定意义的前缀un- unhappy unfinished undressdis- disagree disbelievemis- misbehave mislead mistakenon- nonstop nonsmokerin- [il-(在字母l前)，im- (在字母m,b,p前)，ir- (在字母r前)] inaccurate illegal impolite imbalance irregular（2）表示其他意义的前缀en- “使……”enrich enlarge encourageinter- “相互”international intercontinentalre- “再，又，重”rethink retell recycletele- “远程的”telescope telephone telegraphauto- “自动的”automatic automobileco- “共同”coworker cooperate coexistanti- “反对，抵抗”antiwar antifreeze antinuclearmulti- “多”multistory multicultural multicolor bi- “双，二”bicycle bilingual bilateralmicro- “极小的，微小的”microwave microcomputerover- “太多，过分”overwork overdo overestimateself- “自己，本身”self-centered self-confident self-control under- “在……下面，……下的，不足的”underline underground underestimate underrate2. 后缀（1）形容词后缀-able “可……的，具有……的”acceptable drinkable knowledgeable reasonable-al “与……有关的”physical magical political-an “属于某地方的人”American African-ern “方向”southern northern eastern-ful/ less “（没）有……的”helpful useful homeless hopeless -ish “如……的；有……特征的”foolish childish selfish -ive “有……倾向的”active attractive expensive-en “由……制成的”golden wooden woolen-ous “有（性质）的”famous dangerous poisonous-ly “有……性质的”friendly yearly daily-y “构成形容词”noisy dusty cloudy（2）名词后缀-er / or “表人或用具”farmer baker visitor professor cooker container -ese “某国（人）的”Chinese Japanese-ian “某国、某地人；精通……的人”musician Asian Russian technician-ist “某种主义或职业者”physicist scientist communist socialist-ess “表女性，雌性”hostess actress princess-ment “行为或其状态”government movement achievement -ness “性质，状态”illness sadness carelessness -tion “动作，过程，结果”invention organization translation-ance/ ence “抽象；行为、性质、状态”importance appearance absence existence-th “性质、情况” depth warmth truth-ful “（满的）量”handful spoonful mouthful-(a)bility “抽象、性质、状态”possibility disability reliability -al “过程、状态”survival arrival approval-y “性质、情况”modesty delivery honesty-dom “处于……状态；性质”freedom boredom-age “状态，行为，身份及其结果”courage storage marriage（3）动词后缀-fy / ify “使得；变得”simplify beautify purify-en “使成为……；变得”shorten deepen sadden -ize “使成为”apologize realize specialize（4）副词后缀-ly “方式，程度”freely truly angrily-ward(s) “向……”towards forward upwards（5）数词后缀-teen “十几” fourteen eighteen thirteen-ty “整十位数” forty fifty sixty-th “序数词” twelfth twentieth。