| As an effective L2 teaching and learning mode which combines meaning-centeredness and form-centeredness, the theory Focus on Form has amended the imperfection of inaccurate language use in task-based language learning. This mode has been accepted and supported by many language teachers and scholars. Thereafter a series of researches have been carried out to explore the effective task types to arouse students' attention to language forms.This article reports on the results of a small scale study in which two communicative tasks (Dictogloss & Jigsaw), which were similar in contents but different in format, were used with high school students. Based on the Focus on Form Theory, Input & Output Hypothesis, Noticing Hypothesis together with Collaborative Learning Theory, this study was aimed at exploring the effect of task types on students'attention to linguistic form. By analyzing the numbers of turn-taking and LREs(language-Related Episodes) in students' group discussion about the tasks; meanwhile by analyzing the quality of compositions produced, the researcher intended to find out how students'talks on the tasks affect their output, namely the compositions.The results of the study are as the following.1) Both tasks can arouse students' attention to meaning and form effectively, but Jigsaw does better than Dictogloss in generating students'talk on language form, though the difference is not significant. In Jigsaw task, students talked much more on the usage of verbs and verb phrases than other language forms, and the coverage of their form-based episodes is wider than Dictogloss, which created many LREs on tenses and spelling.2) Students'compositions in Jigsaw task got higher marks than those done through Dictogloss, mainly on contents and organization, but no significant difference was detected on the measurements of vocabulary, morphology and syntax.3) In Dictogloss task, the influence of form-based episodes in students'talk on their compositions is significant; on the contrary, the influence of Jigsaw task is insignificant, some even negatively correlated.The two tasks used in this study can be used as focus-on-form tasks in communicative classroom, which could lead to focus on both meaning and form. The most salient difference is that Dictogloss task may impose a set of constraints while Jigsaw task is relatively open and free to let students expand their thinking. When using these tasks, teachers should consider the practical situation of the class and choose properly to maximize the task effects. |