2.1.3 Classification of Lexical Chunks
Four structural criteria characterize lexical chunks. The first has to do with their length and grammatical status. The second is whether the lexical chunk has a canonical or non-canonical form. The third is whether the lexical chunk is variable or fixed. And the fourth is whether the lexical chunk is continuous or discontinuous, that is whether it consists of an unbroken sequence of words or whether it is interrupted by variable lexical fillers.
In Lewis’s implementing the Lexical Approach, he suggests the taxonomy of lexical items. They are:
1）Collocations, or word partnerships(e.g., Community service)
2）Poly words(e.g., By the way, upside down, to and fro)
3）Institutionalized utterances, or fixed expressions(e.g., I’ll get it; Nice to meet you; how are you?)
4）Sentence heads and frames(e.g., If I were you…) and even text flames (e.g., Firstly...Secondly…) 商务英语信函中的语块研究(3):http://www.youerw.com/yingyu/lunwen_9514.html