1. Background of the Study
As one of the most widely used languages in the world, English is playing anincreasingly important role, which makes learning English more and more popular.Nowadays, learning English is more than just for the sake of taking an examination,and we use it as a tool for communication more and more frequently. For many people,learning English is a slow and painstaking process. Vocabulary, to a great extent, isthe most important aspect in the acquisition of a certain language. Wilkins (1972) putforward that without grammar, very little can be conveyed, but without vocabulary,nothing can be conveyed. There is no doubt that vocabulary learning is a vitalcomponent in the process of learning English, Many learners spend a lot of time andefforts memorizing vocabulary，but still faced with the fact that they achieve little.That is to say，vocabulary learning is a complicated process which needs certainstrategies. The strategies employed by learners are closely related to the outcomes ofvocabulary learning in return.Since 1950s, the research focus of second language acquisition has shifted fromteachers' teaching to students，learning. Therefore, individual differences such as age,sex, motivation, learning styles, and attitude and so on have attracted the researcher'sattention. There are numerous furflier studies related to individual differences, butresearches about factors that may affect learners' use of vocabulary learning strategiesare limited.
2. Purpose and Significance of the Study
On the basis of all the theories and researches on TOA and VLS, the mainpurpose of the present study is，first of all, to identiiy and assess college non-Englishmajors' TOA level, second, to survey the general situations of college non-Englishmajors' use of VLS, third, to investigate the correlation between TOA and collegenon-English majors' use of VLS.To begin with, TOA is an influential factor which can affect English learning,while vocabulary learning is the foundation for and key to the successfiil Englishlearning. If English learners can choose VLS that work best for them according totheir own TOA level, they will leam English vocabulary more effectively, which inturn makes them proficient in English learning. So it is of great significance toexplore the relationship between English learners' TOA level and their VLS use.In addition, although this dissertation is just a case study in SWPU，it can makeus have a general understanding of the correlation between all the college non-Englishmajors' TOA and their use of VLS in Chinese teaching and learning background. Thefindings of this study are expected to provide enlistment for relevant studies in thefuture. On the other hand，since the present study aims at exploring the correlationbetween college non-English majors' TOA and their VLS use, it will doubtlessly raisethe English learners' awareness of TOA and VLS use. What's more, in order toimprove their vocabulary learning proficiency and ability, the learners will find outmore suitable VLS in accordance with their TOA level and their own preference invocabulary learning strategy application.
Chapter OneLiterature Review
1.1 Tolerance of Ambiguity
Ambiguity is one of the main characteristics of the second language learning.Many theorists of foreign language learning and applied linguists hold the view thatsuccessfiil language learning requires a certain TOA.The researches on tolerance ofambiguity focus mainly on psychological domain and can be dated back to the early1950s. This part begins with a general introduction to the definition of TOA fromlinguist and non-linguist perspectives respectively, followed by the measurement ofTOA from different researchers. Finally, the related studies on TOA home and aboardare reviewed. Although TOA stemmed from psychological field，many lingu