A Study of Claims and Qualifiers in ESL Students’ Argumentative Writing --An empirical study based on Toulmin model

English argumentative writing is a difficult point in second language writing. Although there has been a lot of research on English argumentative writing at home and abroad, empirical research focusing on claims in argumentative writing is very scarce. Based on the Toulmin model, this paper studies the relationship between the types of argumentative sentences and English argumentative writing performance from the perspectives of qualifier and claim. By scoring 117 students’ timed argumentative writings, the students’ compositions are divided into high-mark group, medium-mark group and low-mark group. Through the text analysis of each argumentative writing, 23 kinds of claims are extracted and scored according to the qualifying elements of the argumentative. The research shows that the claims in the high-mark group are mostly presented by the qualifying elements in the form of words and claims(QW + C), and the claims are mainly constructed in detailed information. At the same time, it is found that there is no significant correlation between the diversity of qualifying elements in claims and argumentative writing performance.