2. Literature Review
2.1 Definition and Classification
Firth was the first to put forward the notion “collocation" in 1950s. (Qianyuan，1997:43) He refers to collocation as a relation of “company", which means that the meaning of a word manifests in the word or words that accompany it in a context. The relation between “actual words in habitual company" is referred to by some linguists as syntagmatic relations . The mutual expectancy and dependency of collocations verifies Firth’s thought that language is by nature “on- going".文献综述
Halliday and Hason's definition of collocation stresses the relation between vocabulary and discourse .（Halliday, Hason, 2001:3） Being one of the two aspects of lexical cohesion words in a collocation reflect syntagmatic and paradigmatic relations the latter shown in the co-occurrence of opposites and in unordered series cohesion can also be achieved by semantically unrelated words co-occurring in a given context.
Sinclare defines collocation as “the co-occurrence of two Or more words within a short space of each other in a text”. ( Sinclare, J. 2000: 170) By means of computer concordance corpus linguistics studies. The collocation of a given node within a certain span. Lexical co-occurrence is more or less independent of grammatical patterns and positional relationship.
J.R Firth defines collocation as the company words keep their relationships with other words. (Qianyuan，1997:105) Another definition might be the way words combine in predictable ways. When we think of the number of words in English, the number of potential combinations runs into many millions. Each word has its own meaning which is not only defined in dictionary but also the meaning in a phrase. We need know both meanings of a word. We know many expressions of the words which are heard frequently in our daily life. So we just keep them in mind as “one word”. For example, “Crystal clear”, and also some “compound noun”, like “riding boots” or “motor cyclist”. These expressions that are one kind of collocated pairs of words are used everyday by us which have already been fixed like “one word”. In language teaching, collocation is a very interesting area, because they can be found in many parts of the language studying, such as in a syntactic relation, lexical relation, or they can be in no linguistically defined relation. Knowing collocations well is a key point to use well of a language. Sometimes, we can not just judge a sentence only though whether its grammar is right or not.
Lewis classified vocabulary collocations into the following types:
(1) Strong: The combinations of many collocations are very strict or fixed, for example,“a white lie”.
(2) Weak: Some things can be long or short, can be cheap or expensive and also can be good or bad, but some things can be predicted previously, for example,“white coffee“ and “black coffee”.So they are called collocations.
(3) Medium Strength: It is between the two above. For example, “hold a meeting” and “carry out a project”.(Lewis, 1997:37)来.自/优尔论|文-网www.youerw.com/
Vocabulary acquisition has always been penetrating into the whole process of English teaching. Mastering the collocational relationships of a variety of words takes a crucial role in improving the pragmatic level of the students. English collocation focus on the use of words, And by the use of words to deepen the memory of words.
2.2 Previous Studies on English Collocations
Some scholars had done research on the importance of word collocations in building up students’ vocabulary, including: McCarthy believes that “in vocabulary teaching there is a high importance of collocation” and he describes that "collocation is fundamental in the study of vocabulary, and collocation is an important organizing principle in the vocabulary of any language. (McCarthy, 1990: 20) And Firth holds that in order to understand a word, we should first look at the relationship with other words. Meaning exits in the language, and it depends on the word.(Firth, 2000:12) 词语搭配与中学英语词汇教学(2):http://www.youerw.com/yingyu/lunwen_74386.html