Although there are several corpus-based studies on English lexical items, few of them focus on English synonyms comparing to the studies of polysemy, especially on a set of synonymous verbs and their internal syntactic or semantic patterns, just as what Divjak (2006) has clearly claimed in a study of a synonymous set。 

As an advanced lexical research method, the corpus-based behavioral profile (BP) study combines corpus and behavioral profile together so as to figure out the unique syntactic and semantic distributional patterns and of lexical issues (e。g。 the linguistic contexts and collocates)。 

The present corpus-based BP study investigates a group of synonymous verbs--- imply, indicate, signify, and suggest and tries to explore the syntactic and collocation patterns (e。g。 the types of complements and colligation), as well as some internal semantic and usage differences (e。g。 semantic preference and semantic prosody)。 

1。2 Significance and aims of the present study

Verbs are regard as a dominant structural part of speech, composing the key of lexical and grammatical systems of a language。 They serve as predicates, defining or describing the subjects, and are integral in forming sentences。 Besides that verbs are specialized in their complexity in the collocation and semantic structures。 Usually a verb has more than one meaning, collocation and colligation pattern, also varies in form。 Verbs can be classified into three types: simple (e。g。 review and book), compound (e。g。 ill-treat and dry-clean), and derivational verbs (i。e。 those derived from nouns or adjectives, e。g。 enlarge and redden)。 The first genre contains the largest amount of verbs, and the four synonymous verbs identified in the current study all belong to this genre。 

Considering the meanings and classifications of the four selected verbs in this study, current dictionaries and thesauri referred (e。g。 The Oxford Thesaurus An A-Z Dictionary of Synonyms 2008, Longman Synonym Dictionary 1986, The American Heritage Dictionary of the English Language 2006, Oxford English Dictionary (OED) 2008 , Webster’s New Dictionary of Synonyms 1984, The Oxford Dictionary of American English 2005) provided the same general definition for the target synonymous verbs in the set: to express or denote indirectly。 We can get some valuable information about the complex semantic functions of the synonymous set, but they are inadequate in a few important way。 Firstly, the references do not include specific information of various usages of the verbs。 Instead, most of them use rather vague frequency verbs, e。g。 “often” and “usually”, or in terms of the other verbs in this set (signify and indicate being most closely related) to describe different functions of the verbs。 For example, The Oxford Thesaurus An A-Z Dictionary of Synonyms (2008) defines signify as meaning “indicate” and “suggest”, the two other synonymous verbs being indentified。 Moreover, the definitions of suggest are considerably same as those of signify and indicate, only with the additional meanings of “calling to mind” and “leading one to think or believe” in some cases。 Chances are that sometimes they fail to offer enough information about the most dominant semantic function(s) each verb processes。 Fortunately, corpus-based BP study is an effective method which will make up for this information gap。 Second, there are not enough usage patterns (e。g。 collocation and colligation) and semantic features (e。g。 semantic preference and prosody) about these verbs, especially imply。 The present study will not only try to add new findings to the existing descriptions, but also to verify some mentioned existing descriptions of the synonymous verbs。

Moreover, with the development of sophisticated computer science and Internet technology, the corpus-based linguistic method has widely applied in language teaching。 In the compilation of teaching materials, the corpus-based linguistics method can be employed to analyze the materials in textbooks and quantify teaching objectives and targets, determining whether they have met the norms or not。 Therefore, the teaching materials and syllabus will be more accurate in description, more conducive in language teaching and learning, more scientific in system。 And this method can also put all the materials from the textbooks, including texts and exercises, into computer and establish more suitable data for teaching。 In the course of teaching, the teacher can find the examples in the previous texts through the corpus or offer some distinctive collocation and semantic features of the item to deepen the students’ impression。 After class, allowing students to analyze the syntactic and semantic features of lexical items by contacting with the authentic data initiatively can enhance their learning efficiency and activate their enthusiasm for learning at the same time。