Lexical chunks are unities of grammar, meaning and context. Through comprehensive study, researchers summarize three features of lexical chunks: First, they are relatively steady in form. As with common collocations, these prefabricated   chunks stored in our minds are readily made and have grammatical foundations in themselves that can be analyzed. Second, lexical chunks have integral meaning. For some typical lexical chunks, it is difficult to explain its formation with generative grammar, but they do have definite meaning. Take the phrase “by and large” as an example, it is tangled in terms of inner structure and doesn’t accord with grammatical rules, but it is acceptable when used to express large quantity in apt context. For another example, if the sentence “How do you do?” is interpreted only on the literal level, the true meaning won’t be conveyed. Third, contrasted with locutions like “kick the bucket”, “raining cats and dogs”, lexical chunks are more flexible in producing new sentences. Besides, it is generally acknowledged that there are four types of lexical chunks, which are words and poly-words, high frequency collocations, institutionalized utterances and sentence frames. Ranging from vocabulary level to sentence level, the inner word components in some kinds of lexical chunks tend to become more and more disperse, speakers can use such structures to produce new sentences which are matching with the context. Therefore, through the application of lexical chunks, students will be able to acquire vocabulary creatively. 论词块理论在高中英语词汇教学中的应用(2):http://www.youerw.com/yingyu/lunwen_35741.html