摘要：The present study investigated: (a) the effect of output requirement on the acquisition of grammatical collocations; and (b) the relative efficacy of output tasks in comparison with that of input enhancement with regard to the acquisition of grammatical collocations. Ninety homogenous adult Iranian intermediate EFL learners were randomly assigned to two experimental (EG1/EG2) and a control group (CG). A pre-test was given to the three groups to measure the students’ knowledge of collocations prior to any treatment. The students in EG1 were required to do certain output tasks dealing with the collocations in focus after reading a passage whereas for those in EG2 the same target forms were visually enhanced. The students in the CG received neither visually enhanced input, nor output tasks and they were asked to simply read the passage, and answer some questions about it. After the treatment phase, a post-test was administered to measure the gains. The results indicated that both output and input enhancement exert a significant effect on the acquisition of grammatical collocations by the learners. It was also found that input enhancement group outperformed the output group; however; the observed difference was not statistically significant. Accordingly, it can be claimed that an implicit and unobtrusive method such as input enhancement can be as effective as an output task which requires actual production of language on the part of L2 learners.
