Research shows that written corrective feedback (CF) can facilitate improved grammatical accuracy in second language learners’ new pieces of writing. However, scholars have not yet identified whether accuracy improvement is a result of the development of explicit knowledge, implicit knowledge, or both. This study examines the comparative effects of highly focused and mid-focused metalinguistic CF on explicit and implicit knowledge of regular and irregular past tense forms. Fifty-eight low-intermediate Englishasaforeignlanguage (EFL) learners in a first-year English program at a Thai university were randomly assigned to a highly focused group, a mid-focused group, and a control group. The two treatment groups attended a 4-week intervention, where they completed three story rewriting tasks with an experienced EFL instructor and received respective feedback on their errors. Treatment effects were assessed at a pretest and two posttests using an error correction task, a timed grammaticality judgment test, and a timed picture description task. Results revealed that the highly focused and mid-focused groups significantly outperformed the control group on all outcome measures for regular but not for irregular past tense forms, with no significant differences between the two treatment groups. The findings are discussed with pedagogical implications for similar contexts.

研究表明，书面纠正反馈（CF）可以促进第二语言学习者的新写作中语法准确性的提高。但是，学者们尚未确定准确性的提高是否是显性知识，隐性知识或两者的发展的结果。这项研究检验了高度集中和中等集中的元语言CF对规则和不规则过去时形式的显性和隐性知识的比较效果。在泰国一所大学的一年级英语课程中，有58名低中级英语外语（EFL）学习者被随机分配到一个高度集中的小组，一个中等集中的小组和一个对照组。两个治疗组参加了为期4周的干预，在这里，他们与经验丰富的EFL老师一起完成了三篇故事改写任务，并收到了有关他们的错误的反馈。使用纠错任务，定时语法判断测试和定时图片描述任务在预测试和两次后测试中评估治疗效果。结果显示，对于常规的过去时形式，但对于非常规的过去时态形式，高度集中和中等集中的组在所有结果测量上均明显优于对照组，两个治疗组之间没有显着差异。讨论结果对类似情况具有教学意义。结果显示，对于常规的过去时形式，但对于非常规的过去时态形式，高度集中和中等集中的组在所有结果测量上均明显优于对照组，两个治疗组之间没有显着差异。讨论结果对类似情况具有教学意义。结果显示，对于常规的过去时形式，但对于非常规的过去时态形式，高度集中和中等集中的组在所有结果测量上均明显优于对照组，两个治疗组之间没有显着差异。讨论结果对类似情况具有教学意义。