| There are tremendous amount of researches into the nature of language, in which the exploration into the nature and rules of language comprehension is most attractive. Being the fundamental form and the core of language comprehension, sentence comprehension or processing mainly involves syntactic processing and semantic processing.Related researches adopted semantic anomaly (e.g. Some people alarm books.)and syntactic anomaly(e.g. Some people loves books.)(that is , on the basis of sentence integrity, a certain word is semantically or syntactically anomalous.)to evoke the cognitive conflicts to demonstrate their relationship.By reaction times paradigm, some researchers probed into syntactic and semantic processing and relationship between them and built up four theoretical models. Principle-based models indicate syntactic knowledge is applied prior to, and independently of, other types of linguistic and real world knowledge including any semantic processing which only become available later in the course of on-line interpretation. The constraint-based models, in contrast, emphasize the role of syntactic and semantic lexical constraints, and assume that syntactic and semantic processes are not rigidly ordered and describe ambiguity resolution as an interactive process, in which syntactic, lexical, and semantic-conceptual information interacts to constrain on-line comprehension. The concurrent theory holds that there is no strict processing sequences between syntax and semantics, all structures in consistent with the bottom-up information of syntax will be understood in a parallel way and beyond the limitation of semantics. The competition model proposes that cue processing centered on grammatical rules has a determinant effect on sentence comprehension. The above divergence resulted from the data collected by behavioral technique which failed to explain the ongoing processes of sentence comprehension and its time course. Therefore, we must use a kind of technique which allows individual processes to be more successfully isolated as they occur in real time during sentence comprehension, has a more direct measure of the timing of the anomaly detection and examines the scalp electrical activity through the whole sentence without any conscious intrusions.Beginning with the pioneering work of Kutas and Hillyard, a large body of evidence has demonstrated that scalp-recorded event-related brain potentials (ERPs) are sensitive to particular aspects of sentence processing (McKinnon & Osterhout, 1996). Compared with reaction paradigm, ERP can provide the reaction times and scalp activities without interference task and subjects'conscious judgments, so we can take a time-locked online measurement. And the experimenters can adopt off-line to analyze the data, thereby tightly combine the cognitive processes of sentence processing and underlying neurophysiologic activities.Now, ERP researches on sentence processing have provided implications for the neurocognitive mechanisms of first language processing. Researchers confirmed that semantic and syntactic anomaly elicits ERP components of different nature (e.g. semantic anomaly evokes N400, syntactic anomaly involves ELAN,LAN and P600) and thereby constructed some more persuasive neurocognitive model or theory, which greatly pushed the researches in the field.However, compared with first language researches, researches into second language processing is at the stage of exploration and verification. The findings of semantic processing from second language ERP researches were identical with that of first language researches: semantic anomaly evokes N400 but the amplitude was smaller than that of native speakers, its latency was somewhat delayed. Even some researches indicated that there was no difference between first and second language. In contrast, findings about second language syntactic processing were inconsistent with that of first language. Many researches found for late second language learners, second language proficiency and the similarity between first and second language directly influenced second language comprehension, but for specific finding and theoretical explanation, discrepancies remained. Two keys to the question lie in: first, previous researches paid little attention to how second language learners understand syntactic structures of second language. Taking English for example, recent ERP researches mainly involved into phrase structure and subject-verb agreement, but not some important morphology and grammatical structures, e.g. voice and mood, which failed to be greatly generalized. Second, a serial of researches have confirmed syntactic processing of second language was influenced by similarities between syntactic structures and language proficiency, but it remains to know which one holds priority. Furthermore, most of related studies were run by English and other Indo-European languages with close relation to English language as subjects'native languages(for instance, German, Dutch, and Spanish), or English as their second or foreign language, less attention was paid to Chinese ESL learners. It is well known that Chinese is an ideograph with no morphological changes, while English has a rich morphological body. A good case in point is the inflected form of a verb besides the gender and number agreement. Will these great differences lead to specific characteristics in neurocognitive mechanisms of Chinese ESL learners'sentence processing? Studies on the mechanism of Chinese ESL learners second language processing can provide the new and useful evidence for sentence comprehension.Meanwhile, in terms of the above limitation of previous studies, the research chose the important syntactic structure---passive voice. According to the relation between English passive voice and Chinese sentence pattern, passive sentences which can be directly translated into Chinese without word order changes and passive sentences whose word order must be changed according to sentence meaning and comprehension habit chose as materials, and in the light of information types and difficulties required to judge passive sentences, the study explored into the influence of proficiency on passive sentence processing by three experiments. The information includes: 1. whether the form of verbs is be+ V-ed or be+ V-en; 2. whether the past participle of verbs is correct; 3.whether the relationship between subject and predict is plausible.Experiment 1 manipulated four conditions including correct sentence, syntactic anomaly, semantic and double anomaly. The findings revealed that reaction times and correctness rates of high proficient ESL learners are faster and higher than those of intermediate proficient ESL learners, which indicated that proficiency can predict the degree and level of real processing of passive sentences. P200, N400 and P600 were observed under all four conditions; identical with the pattern involved in syntactic anomaly, robust P600 evoked by double anomaly was observed in high proficient ESL learners; for intermediate learners, significant N400 in semantic and double anomaly was observed; there was difference in nature between high and intermediate learners in terms of passive sentence processing ---the former centered on syntactic information, the latter on semantic information; behavioral indicator supported syntactic similarity between languages---reaction times of literal translation sentences were faster, correctness rate was higher; free translation sentences were slower and of lower correctness rate, which was more obvious in intermediate learners. ERP index failed to observe substantial differences, but P200 under literal translation sentence condition was larger. N400 and P600 were also different in each electrode: literal translation sentences evoked larger P600, while free translation sentences elicited larger N400.Experiment 2 manipulated three levels of syntactic information including the original forms of verbs,misuse of past participles and be+V-ing, to further investigate whether proficiency influences the processing mechanisms of ESL learners, especially syntactic processing as the moderating variable.The findings showed that ERP components related to syntactic similarity between languages and proficiency effect were identical with Experiment 1. What'more,"original forms of verbs"elicited an obvious N400 while misuse of past participles evoked a robust P600. Learners of high proficiency were more sensitive to these three kinds of syntactic anomalies than intermediate learners.Experiment 3 manipulated the semantic complexity of verbs and subjects in the sentences, to destroy the semantic re-analysis of possible subject-predicative relationship to further probe into the processing mechanisms of English passiveness in Chinese ESL learners and its relationship with learners'proficiency. Specifically, Experiment 3 included three sub-experiments. The anomaly conditions of Sub-experiment 1 were identical with those of Experiment 1, except that semantic accessibility of predicative verbs was changed which lead to the difficulties of semantic information retrieval. The findings revealed that besides syntactic similarity between languages,proficiency effect and ERP components similar to Experiment 1, double anomaly and semantic anomaly evoked significant N400, correct sentences and syntactic anomaly elicited no negative N400; P600 evoked by syntactic anomaly and double anomaly was robust; the amplitudes of P600 in learners of high proficiency were obviously larger than those of intermediate learners. The anomaly conditions of Sub-experiment 2 were identical with those ofExperiment 2, except that semantic accessibility of predicative verbs was changed which lead to the difficulties of semantic information retrieval. The findings revealed that except proficiency effect and ERP components similar to Experiment 1, no syntactic similarity between languages and N400 were found; P600 evoked by correct sentences was largest.The sub-experiment 3 manipulated the semantic accessibility of the patients (subjects of the sentences), and adopted anomaly conditions similar to Experiment 1. The findings showed besides syntactic similarity between languages, proficiency effect and ERP components similar to Experiment 1, N400 and P600 elicited by semantic anomaly or double anomaly are the largest; P600 in learners of high proficiency was larger than that in intermediate learners. According to the above findings, the study achieved three breakthroughs: first, the development of semantic processing and syntactic processing was imbalanced in sentence processing of second language. Under the current experiment condition, both behavioral data and ERP data revealed that second language proficiency had imbalanced influence on sentence processing of second language. Specifically, semantic processing capacity of ESL learners was greater, and received no influence from learners'proficiency, which was confirmed by the facts that two types of learners showed no difference in semantic processing under all the experimental conditions. But as to syntactic processing, there were significant differences between the two types of learners, which was the determinant factor for whether sentences could be appropriately understood. The findings of each experiments showed learners of high proficiency had formed the stable automatic processing pattern to judge whether the past participles of the verbs (referred to the core information in the judgment of English passiveness) are correct. When word meaning was difficult for retrieval, this above pattern was destroyed and syntactic processing of these proficient learners became similar to those intermediate learners. The intermediate learners were sensitive to obviously incorrect syntactic information.For second language learners, the study found that sentence processing was dynamic. That is, learners drove semantic or syntactic processing according to the importance or dominance of semantic information based on their own level. Therefore, semantic and syntactic processing exhibited more parallel but not sequential, to say, the followings predicted by semantic attraction and the eADM would occur: semantic and syntactic processing could be of independency,compatibility and switchover. So three-phase nuerocognitive model was not applicable to explain the mechanism of second language learners. As to the complex syntactic structure like passiveness, learners would take a quick search and detection, and select their automatic processing strategy---intermediate learners tended to process semantic information while learners of high proficiency processed syntactic information first. What's more, intermediate learners applied memorized"mental lexicon"but not computational"mental grammar"to analyze and judge the passive forms of verbs. Many studies revealed that memorized"mental lexicon"separates from computational"mental grammar"on the neural basis and function. That is, English inner rule systems of intermediate learners failed to internalize the syntactic rules of passiveness. On the contrary, learners of high proficiency could combine memorized"mental lexicon"and computational"mental grammar"to analyze and judge the passiveness.Third, the study partially confirmed transfer effect---syntactic similarity between first and second languages. Specifically, under simple semantic information condition, the findings were identical with theoretical expectation. The findings were in conformity with syntactic similarity effect described in the precious studies. However, when the semantic accessibility of the critical words was destroyed, brain activities revealed by ERP went into reverse: literal translation sentences evoked a greater N400 than free translation sentences, while the latter elicited a greater P600.The underlying reasons of these results remain to be explored into.
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