摘要：vocabulary is one of the building blocks in english learning. insufficient vocabularyknowledge of the learners leads to difficulties in english learning. thus，it is quite importantfor learners to leam vocabulary well and that’s the reason why vls get more attentionincreasingly.
chapter one literature review
1.1 strategies
as the terms related to strategies claimed by different researchers are not exactly thesame because of their different study purposes and various perspectives，it is of priornecessity to clarify the important terms of strategies in the present study in the first place. english becomes increasingly important in china as the development of china’sreform and economy. thus, english learning strategies win more popularity in recent years.in the field of learning strategies, a substantial amount of studies have been carried out.and thus，a lot of related definitions of learning strategies have been put forward."learning strategies are the behaviors and thoughts that a learner engages in duringlearning that are intended to influence the learner’s encoding process".(weinstein andmayer，1986: 315-327)"learning strategies are techniques, approaches or deliberate actions that studentstake in order to facilitate the learning and recall of both linguistic and content areainformation?”(chamot，1987: 80)"learning strategies are strategies which contribute to the development of thelanguage system which the learner constructs and affects learning directly."(rubin，1987:15-30)"learning strategies are techniques which students use to comprehend, store, andremember information and skills". (chamot and kupper，1989: 13-24)in another way，ellis (1999: 234-235) points out that one of the best approaches todefine learning strategies is to list their main characteristics:
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1.2 studies on vls training
vocabulary is one of the building blocks in english learning. insufficient vocabularyknowledge of the learners leads to difficulties in english learning. thus，it is quite importantfor learners to leam vocabulary well and that’s the reason why vls get more attentionincreasingly. however, learners incline to use vls not so effectively by themselves. hence,it is necessary to conduct vls training to help learners leam vocabulary effectively. asnation (2001; 167) asserts that "since learners differ greatly in the skill with which theyuse strategies, it is important to make training in strategies use a planned part of avocabulary development program".the field of studies on vls abroad tends to be theory-oriented in the beginning.researchers propose specific definitions, classifications of vls and study theoreticalfoundations and research frame for vls researches. most researches on vls haveexplored different methods of vocabulary learning and most studies are memory strategies.some earlier researches on vocabulary learning focus on rehearsal strategies andrepetitions. (crothers&suppes，1967; lado，baldwin, & lobo，1967) in the past threedecades, following atkinson (1975) and atkinson and raugh(1975), vls researches havefocused on the key-word method，which means finding a keyword in one’s first languagethat sounds like the foreign word，and then, connects the keyword and the foreign word byan interactive image.
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chapter two theoretical foundation
2.1 introduction
this chapter will present the theoretical foundation of the present study. however, it isnecessary to briefly review the theoretical foundations in previous studies before thepresentation so as to er understand the reason to make the current choice.in the previous studies, the commonly-used theoretical foundations for strategytraining on english vocabulary learning include the theory of depths of processing (craik& lockhart, 1972)，input hypothesis (krashen, 1982)，interaction hypothesis (long, 1996)and zone of proximal development theory (zpd) (vygotsky, 1978). the first three theoriesbelong to linguistics theories and are very important in the field of english teaching，whichseem appropriate when they are employed in strategy training on language learning. thus’it is natural for researchers like ellis (1997) and nation (1990) to employ these theories intheir studies on vocabulary learning.however，the present study chooses zpd theory, a socio-cultural theory，which hasbeen chosen not as often as other theories to be a theoretical foundation for strategytraining on vocabulary learning, and attempts to prove that zpd theory might be one of themost suitable explanatory frameworks for strategy training.
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2.2 definition of zpd
zpd is one of the major concepts defined by vygotsky. though functions as asociocultural theory to psychology and psycholinguistics, zpd is investigated and appliedfrequently by researchers in the field of english teaching. vygotsky’s thinking on zpd begins to crystallize as he confronts issues relating to iqand iq testing, which are controversial during his time. several of vygotsky’scontemporaries observe，however, that once in school，children with an initially high iqfrequently manifest a decrease in their iq score，while those with low initial iq scoresoften tend to show score gains (van der veer & valsiner，1991). vygotsky (1978) arguesthat one cannot fully understand children’s developmental level without also determiningthat development’s upper boundary, which is determined by the kind of tasks that childrencan do with someone else’s assistance. in other words, two children may exhibit the sameiq score，supposedly indicating that they have achieved the same developmental level andthus readiness for instruction, but one of them might well be able to perform more complextasks under someone else’s guidance than the other could with the same assistance.vygotsky refers to this difference between actual and potential iq as the zpd.
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chapter three methodology........ 29
3.1 research questions........ 29
3.2 participants ........30
3.3 instruments........ 30
3.3.1 questionnaire ........30
3.3.2 test ........ 39
3.4 strategy training........ 41
3.5 data analysis........ 43
chapter four results and discussion........ 44
4.1 analysis on asu........44
4.2 sensitivity of s-st........ 47
4.2.1 scores of strategies........ 47
4.2.2 comparison of strategies........ 51
4.3 vocabulary size ........53
4.4 sensitivity of l-st........ 56
chapter five implications........ 60
5.1 implications on vocabulary teaching........62
5.2 implications on vocabulary learning........66
chapter five implications