Wan Lifang (2010) explored the tendency of lexical richness among Chinese English majoring students from 3 dimensions: lexical variation, lexical sophistication and lexical error. The materials were 200 papers from four universities in Shanghai of TEM-4 in 2003 and TEM-8 in 2005. The results turned out that there is an increasing trend both in lexical sophistication and lexical variation while having a larger number of lexical errors, which means that the growing of vocabulary size is far from enough in improving the quality of an essay. Whether the vocabulary in mind can be used correctly or not matters a lot. Lexical correctness, an extra measurement taken into consideration in this paper, makes it different from others. 不同英语写作水平学生议论文写作词汇丰富性差异研究(3):http://www.youerw.com/yingyu/lunwen_31277.html