英语成语是英语词汇中的重要精华部分（part and parcel）。社会生活的各个方面是英语成语取之不尽的源泉（Idioms from Society），当代英语中最常用的成语有4000余条。许多常用的英语成语来自《圣经》(Bible)和莎士比亚（Shakespeare）等文学名著。英语成语主要是口语，而汉语成语主要是书面语；English idiom 字数不固定，而汉语成语多为四字词组。下面分广义和狭义来论述英语成语。
一、 英语成语的理解
（一）广义的英语成语的理解
从文体学来说，广义的英语成语（idiom）包括谚语（proverb）、俚语(slang)、俗语（colloquial）、成对词（twin words）、三词词组（trinomials）、熟语（catchphrase, lexical phrase ）和习惯搭配（habitual collocation, restricted collocation）等。现举例如下：
1. 谚语、格言(proverb)，警句(sentence idiom)。
英语谚语常有缩写形式，类似汉语的歇后语。例如：
1) Proverbs are children of experience.谚语是经验的产物。
2) It' s no use crying over spilt milk.倒翻牛奶，哭也没用。缩写形式：Cry over spilt milk. 含义：覆水难收。
2. 俚语（slang）。
俚语为某些人群和地区所特有，适用范围有严格限制，使用时要注意其使用的得体性和意义的准确性。例如：
1）screw up 弄糟、一塌胡涂He screwed the whole thing up from start to finish. 他自始至终一塌胡涂。
2）Pay off 贿赂 chat up 与异性搭讪
3. 口语（colloquial）。例如：
snake in the grass 暗箭
hit below the belt \ stab in the back 暗箭伤人
cut the ground from under sb. 在某人背后搞鬼
4. 成对词（twin words, irreversible binomials 或 words in pairs）。英国学者福勒(H.W.Fowler) 把它比作“连体双胞胎”(Siamese twins)，称为重言法（hendiadys）。例如：
beer and skittles 吃喝玩乐，wax and wane 盛衰，weal and woe祸福。
5. 三词词组（trinomials）。有些固定的三词词组也被归为成语，因为它们大都也是一些固定的讲法。例如：
1）sun, moon and stars 日月星on land, on sea, and in the sky 海陆空
2）Eat, drink and be merry. 及时行乐Wine, woman, and song. 吃喝玩乐
(二) 狭义英语成语的理解
狭义的英语成语有以下几个特点(The Characteristics of English Idioms):
1. 长期的习用性（Idiomaticity）。有些谚语有上千年历史。例如：
1）Time flies like an arrow. 光阴似箭。
Art is long, life is short. 人生苦短，艺术长久。
2）A friend in need is a friend indeed. 患难之交。
2. 结构的固定性（Structural Stability, Syntactic Frozenness）。
英语成语的固定性（fixity）取决于它们的习用性（idiomaticity），其习用性越强，结构越固定，就越为人们所接受。 例：sword for sword 剑对剑, tit for tat 针锋相对。 Diamond cut diamond. 棋逢对手。Like cures like. 以毒攻毒。
3. 语义的整体性（Semantic Unity）。
英语成语（idiom）也称为混合词（fused words），理解英语成语的意义要从整体上去把握，因为英语成语的语义是一个独立和完整的内在统一体。例如：
1）rain cats and dogs (meaning: rain heavily) 倾盆大雨
2）wear one's heart upon one's sleeve (meaning: show one's feeling plainly) 心直口快
http://www.oxford.com.cn/study/practice/culture/2005-05-17/2354.html 这个地址是专么讲英语成语分类的。
http://www.ednchina.com/blog/telenglish/7360/message.aspx 这里大概有500个成语
ARCHER TAYLOR
THE ORIGINS OF THE PROVERB*关于英语谚语起源与发展的文章!
THE definition of a proverb is too difficult to repay the undertaking; and should we fortunately combine in a single definition all the essential elements and give each the proper emphasis, we should not even then have a touchstone. An incommunicable quality tells us this sentence is proverbial and that one is not. Hence no definition will enable us to identify positively a sentence as proverbial. Those who do not speak a language can never recognize all its proverbs, and similarly much that is truly proverbial escapes us in Elizabethan and older English. Let us be content with recognizing that a proverb is a saying current among the folk. At least so much of a definition is indisputable, and we shall see and weigh the significance of other elements later.
The origins of the proverb have been little studied. We can only rarely see a proverb actually in the making, and any beliefs we have regarding origins must justify themselves as evident or at least plausible. Proverbs are invented in several ways: some are simple apothegms and platitudes elevated to proverbial dignity, others arise from the symbolic or metaphoric use of an incident, still others imitate already existing proverbs, and some owe their existence to the condensing of a story or fable. It is convenient to distinguish as "learned" proverbs those with a long literary history. This literary history may begin in some apt Biblical or classical phrase, or it may go back to a more recent source. Such "learned" proverbs differ, however, in only this regard from other proverbs. Whatever the later history may be, the manner of ultimate invention of all proverbs, "learned" or "popular," falls under one or another of the preceding heads.
It is not proper to make any distinction in the treatment of "learned" and "popular" proverbs. The same problems exist for all proverbs with the obvious limitation that, in certain cases, historical studies are greatly restricted by the accidents of preservation. We can ordinarily trace the "learned" proverb down a long line of literary tradition, from the classics or the Bible through the Middle Ages to the present, while we may not be so fortunate with every "popular" proverb. For example, Know thyself may very well have been a proverb long before it was attributed to any of the seven wise men or was inscribed on the walls of the temple of Delphic Apollo. Juvenal was nearer the truth when he said it came from Heaven: "E caelo descendit " (Sat., xi, 27). Yet so far as modern life is concerned, the phrase owes its vitality to centuries of bookish tradition. St. Jerome termed Don't look a gift horse in the mouth a common proverb, when he used it to refer to certain writings which he had regarded as free will offerings and which critics had found fault with: "Noli (ut vulgare est proverbium) equi dentes inspicere donati." We cannot hope to discover whether the modern proverb owes its vitality to St. Jerome or to the vernacular tradition on which he was drawing. St. Jerome also took The wearer best knows where the shoe wrings him from Plutarch, but we may conjecture that this proverb, too, was first current on the lips of the folk. Obviously the distinction between "learned" and "popular" is meaningless and is concerned merely with the accidents of history.
PROVERBIAL APOTHEGMS
Often some simple apothegm is repeated so many times that it gains proverbial currency: Live and learn; Mistakes will happen; Them as has gets; Enough is enough; No fool like an old fool; Haste makes waste; Business is business; What's done's done. Characteristic of such proverbs is the absence of metaphor. They consist merely of a bald assertion which is recognized as proverbial only because we have heard it often and because it can be applied to many different situations. It is ordinarily difficult, if not impossible, to determine the age of such proverbial truisms. The simple truths of life have been noted in every age, and it must not surprise us that one such truth has a long recorded history while another has none. It is only chance, for example, that There is a time for everything has a long history in English,--Shakespeare used it in the Comedy of Errors, ii, 2: "There's a time for all things,"--and it is even in the Bible: "To every thing there is a season, and a time to every purpose under the heaven" (Omnia tempus habent, et suis spatiis transeunt universa sub caelo, Eccles. iii, I), while Mistakes will happen or If you want a thing well done, do it yourself have, on the contrary, no history at all.
The full text of this article is published in De Proverbio - Issue 3:1996 & Issue 4:1996, an electronic book, available from amazon.com and other leading Internet booksellers.
PROVERBIAL TYPES
New proverbs have often been made on old models. Certain frames lend themselves readily to the insertion of entirely new ideas. Thus the contrast in Young . . ., old . . . in such a proverb as Young saint, old devil yields a model for Junge Bettschwester, alte Betschwester. A methodical comparison would probably reveal the proverb which gave the original impulse to the formation of the others; but no one has ever undertaken a study of this sort. Martha Lenschau conceives the development as follows: Young angel, old devil (Jung Engel, alt Teufel, thirteenth century); Young soldiers, old beggars (Junge Soldaten, alte Bettler, seventeenth century). The first form made no distinction for sex. When the substitution of "knight" or "soldier" made the distinction, a by-form for women was invented on the same model: Junge Hure, alt Kupplerin appears to have been the first of such by-forms, although Jung Hure, alt Wettermacherin must also be ancient, since the notion involved in "Wettermacherin" reaches far back. The most recent development is probably the Low German Young gamblers, old beggars (Junge Späler, ole Bedler), and the corruption Young musicians, old beggars (Junge Musikanten, alde Beddellüde), which arises from the misunderstanding of "Späler," 'players' (i. e. gamblers), as 'players of music' and the later substitution of a synonym.
It is not always easy to recognize or identify the earliest form which provided the model for later developments; and until several proverbs have been minutely examined from this point of view and our methods of study have been improved, it is hard to say which arguments are safe to use and which are unsafe. In all probability, we may trust to the general principles which have been worked out for märchen, i. e. those employed in the so-called Finnish or historico-geographical method. The relative age and distribution of the various forms of a proverb will throw much light on the development. In the present instance, for example, we might regard the old and widely known Jung gewohnt, alt getan ('What one is accustomed to in youth, one does in old age') as a possible model, even of the whole group. Certainly it has given us Jung gefreut, alt gereut (' Rejoiced in youth, repented in age') and as a secondary development: Jung gefreit, alt gereut ('Married in youth, repented in age'). Since, however, Young saint, old devil is even older and more widely known, I am inclined to consider it the parent of all later forms. Often other arguments than age and wide currency may be brought into court. Usually, a dialectal variation which is essential to a particular form and which limits it to a narrow area is secondary in origin, e. g. Jung gefreit, alt geklait ('Wed in youth, bewailed in old age') can have arisen only in a region where 'geklagt' is pronounced "geklait." So, too, Jung gefreit, alt gereut originated in a region--somewhat larger, to be sure, than the one just mentioned--where the dialectal pronounciation of "gereut" made the rhyme tolerable.
A few more illustrations of the creation of new proverbs on the model of old ones will suffice. A familiar German proverbial type employs the notion that the essential qualities of an object show themselves the very beginning, e. g. Was ein Häkchen werden soll, krümmt sich beizeiten (' Whatever is to be a hook, bends early'). English representatives of this type are rare, but we may cite Timely crooks that tree that will be a cammock (i. e. 'gambrel,' a bent piece of wood used by butchers to hang carcasses on) and It pricketh betimes that shall be a sharp thorn. A German derivative of the type is Was ein Nessel werden soll, brennt beizeiten ('Whatever is to be a nettle, burns early'). This proverb has found rather wide currency. Although the evidence is not all in, the type or at least its ready employment in new proverbs is German. The form characteristic of Es sind nicht alle Jäger die das Horn blasen ('They are not all hunters who blow horns'), a form which appears to have been first recorded by Varro ('Non omnes, qui habent citharam, sunt citharoedi'), enjoyed a remarkable popularity in mediaeval Germany and gave rise to many new proverbs, e. g. They are not all cooks who carry long knives (Es sind nicht alle Köche, die lange Messer tragen); They are not all friends who laugh with you (Zijn niet alle vrienden, die hem toelachen). Outside of Germany and countries allied culturally, the form appears to have had no notable success, except in All is not gold that glitters, which refers to a thing and not a person. Seiler thinks that" Many are called, but few are chosen" (Multi enim sunt vocati, pauci vero electi, Matt. xx, 16; xxii, 14) was the ultimate model for these proverbs, but the similarity is one of thought and not of form. Possibly one could imagine a class based on simple balance and contrast, of which the young-old type and the called-chosen type might both be derivatives, but the fundamental differences in syntactical structure speak strongly against a development of this sort. Young saint, old devil is an old proverbial form which has no verb; Many are called, but few are chosen consists of balanced, antithetical sentences; All is not gold that glitters uses a subordinate clause. The syntactical differences are so great that an influence from one of these types on another does not seem likely.
The full text of this article is published in De Proverbio - Issue 3:1996 & Issue 4:1996, an electronic book, available from amazon.com and other leading Internet booksellers