Semantic lexical chains have been regarded as important in textural cohesion, although traditionally, the classification of these chains has been limited to repetition, synonymy, hyponymy, and collocates. The cases of automatic extraction of lexical chains have found that the contextual synonyms can not be recognized, nor extracted automatically. This study took the data-based technology to extract the contextually co-occurring lexical chains through thematic lexical items. It found that these contextually co-occurring lexical chains can include the semantic lexical chains and contextual synonyms. It also found that, in extraction of collocates of the co-occurring lexical items, these collocates form secondary lexical chains, which contribute to textual cohesion. The vertical lexical chains made of contextually cooccurring lexical items and the horizontal chains made of collocational lexical items work together in making the text into a coherent whole.
理工科院校研究生英语教学转向学术英语(English for Academic Purposes,EAP)或者专用英语(English for Specialized Purposes,ESP)已经成为共识,然而转型却存在诸多困难。本文从指导政策、考试评估、师资力量等方面分析了限制理工科院校研究生英语教改顺利进行的因素。在此基础上,结合理工科专业英语学习的特点,提出要加大政策引导、改革现有考核方式和创新师资培养模式,从而更好地实现向EAP/ESP教学转变。
