Although uninterpretable features are claimed to be an area of difficulty for EFL learners, they are still one of the less explored areas of research in the field of L2 pedagogy. The present study sought to investigate the impacts of two techniques, namely contrastive analysis and dictogloss on EFL learners’ mastery of resumptive pronouns, an uninterpretable feature absent in English relative clauses but present in most Persian ones. To this end, 77 elementary EFL learners with similar background in English were selected and assigned to three groups: one control and two experimental. Before and after the instruction the participants were administered a 50-item Grammaticality Judgment test and a 20-item translation test which had been developed and validated for use in this study. The results showed that all three groups had significant progression after the treatments, but the comparison among the groups indicated no statistically significant difference. This may suggest that   L2 exposure had a more important role in the participants’ performance than the instruction type (contrastive analysis and dictogloss). The findings seem to support the importance of exposure to such L2 structures over time and that instruction cannot always accelerate acquisition.