The purpose of this study is to investigate the errors concerning V-ing forms in Korean college freshmen’s English essays in order to provide some guidelines for teaching the forms effectively. The data for this study were retrieved from a learner corpus consisting of 815 essays written by Korean college freshmen. A total of 3,843 words were found in the form of V-ing, which were categorized according to their roles as follows: (a) present participles (1,235 tokens), (b) gerunds (2,591 tokens), and (c) unclear cases (17 tokens). Of the 3,843 forms of V-ing, a total of 292 tokens were classified as erroneous, 137 of which were participle-related errors and 138 gerundrelated errors. The most frequently occurring errors under the categories of present participles and gerunds were the use of a present particle without a main verb (64.2%) (e.g. I *looking for the meaning of the building’s name) and to-infinitive related errors (66.7%) (e.g. Therefore, we try to *changing our college’s image), respectively. Pedagogical suggestions based on the findings of the study are also provided at the end.

This study aims to investigate the errors of prepositional verbs in Korean university students' essays and alert teachers to the necessity of a more systematic instruction of prepositional verbs. Prepositional-verb errors found in the learner corpus of essays written by 416 Korean university students were classified into five categories: (a) preposition omission, (b) wrong prepositions, (c) preposition addition, (d) misordering, and (e) others. Of the 1317 tokens of prepositional verbs retrieved from the corpus, 448 were found to be used erroneously, over half of which were instances of preposition omission. No tokens of misordering errors were found (e.g., *to go school / *go school to). A careful analysis of these errors also revealed the following. First, students were not able to discern the difference between a verb used transitively and the same verb used as a prepositional verb (e.g., believe and believe in). Second, the inability to distinguish transitive verbs from intransitive ones also resulted in a considerable number of errors in preposition omission (e.g., *listen music) and preposition addition (e.g., *enter in university). Third, using wrong prepositions (e.g., *worried at me) was also a rather common occurrence, accounting for 18% of the all the errors related to prepositional verbs.