How languages are acquired and what stages learners go through has been the focus in language teaching area, and this cross-sectional study investigated the use of English adverbs by elementary, pre-intermediate and intermediate level Turkish EFL students at Anadolu University School of Foreign Languages by analyzing it from acquisitional perspective. Specifically, it explored (a) whether the accuracy of adverb placement by the students varied in terms of the types of tasks that the participants carried out; (b) whether the accuracy of adverb positioning varied in terms of the proficiency levels; and (c) whether problematic structures in adverb placement differ regarding language proficiency. The data were collected through two task types: a grammaticality judgment task (GJT) and a written production task. The data were collected during regular class hour and analyzed using descriptive statistics. The results of these tasks revealed that the accuracy of adverb placement by students varies with respect to the types of tasks and their proficiency levels. The analysis of the data has shown that Turkish L2 learners of English demonstrate development differences both in their grammaticality judgment tasks and production tasks, and this may be related to Full Access/Full Transfer Hypothesis as at the beginning of the acquisition, the learners have resort to their L1 more because it forms the basis for them until they have full access to UG.