Thi s study investi gates whether the effect of written corrective feedback (CF) on learners' acquisition of English art icle usage is mediated by the type of information CF provides. To tap into this issue, four types of informat ion on error were identifi ed: its existence, location, correct form and nature. Written CF was categorized into three types according to the sorts of information it contained: indirect CF that supplies informat ion on existence and location, direct CF that provides information on ex istence, location and correct form, and metalinguistic CF that includes metalinguistic explanation on error nature and all the other infornlation types. Three CF groups were accord ingly formed along with a control group in a quasi-experiment, where the groups engaged in three narrative-writing tasks. Error correction and narrati ve writing tests were administered to measure the acquisition of explicit and implicit knowledge of English articles respectively. The results revealed that written CF was beneficial to acquisition of both L2 exp licit and im plicit knowledge and that such positive effects emerged only in the metalinguistic CF group. The findings added counterevidence to Truscott's (1996) argument against written CF utility and suggested that metalinguistic explanation on error may playa pivotal role in written CF-triggered L2 acqui sition.

I. INTRODUCTION
II. BACKGROUND
    1. Distinction between Oral and Written CF
    2. Integration of Written CF in SLA Research
III. METHOD
    1. DeSign
    2. Participants
    3. Target Structure
    4. Sorts of Acquisition for Measurement
    5. Tests for Assessing Acquisition
    6. Treatment Tasks
    7. Procedure
    8. Data Analysis
IV. RESULTS
V. DISCUSSION
VI. CONCLUSION
REFERENCES

• Sung-Soo Jang(College of General Education Inje University)