## 6 Conclusions  
Prior research studies have supported that a significantly positive correlation exists between vocabulary knowledge and EPT performances [11; 15; 26; 48; 49]. EFL learners' vocabulary size is crucial for comprehending English contexts--that is, better vocabulary knowledge brings out higher lexical coverage and a better understanding of English contexts [20; 26; 29; 30; 31]. Based on the lexical threshold theory, this study adopted the corpus-based approach to explore the lexical difficulty tendency of MOEPT, as developed by a Taiwanese military academy. The findings presented have important implications for the future development and updating of MOEPT. Moreover, for English pedagogical implications, the findings are vital indicators for setting vocabulary goals, selecting materials and lexical tasks, designing lexical syllabi, or even monitoring cadets' vocabulary learning progress. This paper has the following contributions. First, the word classification process has successfully separated the word types and tokens of the target corpus into function words, CEFR A2 level words, CEFR B1 level words, and off-list words in a machined-based way. Furthermore, off-list words have also been investigated to further be divided into sub-classifications, including other EGP words, Name, Country/Location, Military, and Medical by the qualitative vocabulary taxonomy that was conducted by the three raters, which made the composition of the target corpus be more clearly anatomized. Second, the corpus-based word classification method used for the detection of difficulty level can be replicated and used to explore any EPT corpus data (e.g., entrance exams, TOEFL, and IELTS). Third, the TCEEC word list, including CEFR A2 and B1 level word lists, is well-known within Taiwan's education system [43]. Thus, this difficulty level analysis will allow Taiwanese teachers and students to immediately understand the trend of EPT that they want to analyze. To summarize, although MOEPT may not be a representative EPT sample, the proposed corpus-based word classification method is still capable of unveiling the mystery of the difficulty level of any EPT and can be utilized widely. This paper still has some limitations. For example, unlike IRT, this corpus-based analysis did not take EFL learners' English competency into consideration or integrally analyze the correlation between cadets' English competency and MOEPT difficulty tendency. Moreover, the reliability and validity of MOEPT were not explored and discussed in this study. Future researchers can rely on the present study to develop different difficulty level word lists as measurement tools to conduct more extensive corpus analysis and to conduct in-depth evaluations of the reliability and validity of EPT by integrating information on linguistic aspects. Other factors may affect test analysis, including average text length, percentage of complex words, percentage of parts of speech, and readability indices, can also be discussed in the future (e.g., [50; 51]). In addition, exploring the relationships between tests, pedagogical design and practice, learning strategy, the washback effect, and an external monitoring mechanism can help ensure that the curriculum does not deviate from the test preparation tendency (e.g., [52; 53; 54; 55; 56]). Conceptualization, L.-C.C. and K.-H.C.; methodology, L.-C.C. ; software, L.-C.C., S.-C.Y. and S.-C.C. ; validation, L.-C.C. and K.-H.C.; formal analysis, L.-C.C. ; investigation, L.-C.C. ; resources, L.-C.C. and K.-H.C.; data curation, L.-C.C., K.-H.C., S.-C.Y. and S.-C.C. ; writing--original draft preparation, L.-C.C. ; writing--review and editing, L.-C.C., K.-H.C. and S.-C.Y. ; supervision, K.-H.C.; funding acquisition, K.-H.C. All authors have read and agreed to the published version of the manuscript. The authors would like to thank the National Science and Technology Council, Taiwan, for financially supporting this research under Contract No. MOST 110-2410-H-145-001 and MOST 111-2221-E-145-003. Not applicable.