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。
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。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。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。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。How long have you lived there?你在那儿住多久了？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”。
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（compounds）。合成词的写法由习惯决定，可以写在一起，也可以用连词符号连接。
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-chief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+形容词 ten-year-old 800-meter-long名词+to+名词 face –to-face door - to -door副词+动词 outnumber underestimate overwork介词＋名词 beforehand overhead代词宾格＋self/selves herself themselves物主代词＋self/selves myself yourselves
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。
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。un-unhappy unfinished undressin[il-(在字母l前)，im-(在字母m,b,p前)，ir(在字母r前)]-inaccurate illegal impolite imbalance irregularmis-misbehave mislead mistakeen-“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 multicolorbi-“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-controlunder-“在……下面，……下的，不足的” underline, underground, underestimate, underrate-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-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-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, angrilyward(s)“向……” towards, forward, upwards-teen“十几” fourteen, eighteen, thirteen-ty“整十位数” forty, fifty, sixty-th“序数词” twelfth, twentieth英语要想取得好成绩，词汇这关必须要过！高考要求考生词汇量要达到3500左右，中考要求考生词汇量达到1600左右，记忆单词不仅要抓重点，而且还要讲究方法。
