This study sought to investigate the effects of Explicit Instruction in combination with Input Enhancement (EI+IE), Input Flood (IF), and Gap-fill (GF) tasks on receptive and productive knowledge of English formulaic sequences (FS) by Iranian intermediate EFL learners. Assigned to three experimental groups , the 110 participants took the receptive and productive knowledge pretests, posttests, and delayed posttests. Findings of within-group (repeated- measures ANOVAs) and between-group (ANCOVAs) tests showed that while IF could not promote learners' performance, both the EI+IE and the GF could improve learners’ receptive and productive knowledge of target FSs from pretests to posttests and retained the effects until the delayed posttests. Additionally, both EI+IE and GF groups significantly outperformed the IF group at the immediate posttests. That is, the results from EI+IE did not differ significantly from those of GF. Plausible accounts for the obtained results are provided and the implications are discussed.
