Abstract-This study aimed at investigating the effect of lexical simplification and elaboration on Iranian intermediate EFL learners' learning and retention of phrasal verbs. In order to achieve this goal, a PET test was run into 130 learners. When target participants were chosen, they were assigned into three groups including two treatment groups and one control group. Through a multiple choice test, 40 out of 60 phrasal verbs were selected as target phrasal verbs. Through 8 sessions of treatment, each group received a reading comprehension text that contained 5 phrasal verbs. But the way the phrasal verbs in two experimental groups were modified was different. One of them received elaborated input and the other group received simplified input; meanwhile, the control group received unmodified input. After eight sessions of treatment, an immediate multiple choice test was administered to find out which techniques had stronger effect on participant's learning and retention of phrasal verbs. After one month, the same test, with a different order of items, was administered as delayed posttest to check the participants' level of retention. According to the results of the study simplified input group significantly outperformed the control and elaborated group on both learning and retention of phrasal verbs.

A number of studies have displayed the significance of focusing on form in L2 learners' acquisition of morphosyntactic features. This study compares the effects of three focus-on-form tasks (input enhancement, individual output, and collaborative output) on the acquisition of English subjunctive mood. The learners' trend of development in the subjunctive mood acquisition process is also investigated. Ninety freshmen from a B.A. program in TEFL were randomly divided into the three task groups. These tasks included textual enhancement in Group 1, and dictogloss in Group 2 and 3, where texts were reconstructed individually and collaboratively, respectively. A time-series design was used to measure progress in the participants' production of the target feature; in conjunction with a pretest and a posttest, three production tests were given to assess the trend of development in each group. The study revealed that the impact of input and collaborative output tasks was greater than that of the individual output task. Moreover, the findings showed that the trend of development in the individual output group was not a linear additive process, but a rather U-shaped one with backsliding. This study supports previous studies that have combined both enhancement and instructional assistance. It also adds further importance to the effectiveness of collaborative interaction in the acquisition of English structures.