From an L2 experimental perspective, the present paper aims at shedding new lights on the nature and the source of exhaustiveness in the two English constructions: (i) ‘it’-clefts; ‘only’-foci. We report experimental evidence that the cancellation of the exhaustiveness construal normally available to the constructions at issue gives rise to different processing costs. Specifically, we provide the results by comparing the ERP patterns that arise when the (marked) cancellation of exhaustiveness is processed in either ‘it’-clefts or ‘only’-foci. Our findings show that during on-line sentence processing, highly proficient Korean English leaners can discern the two different types of exhaustiveness, which in turn indicates that they can recruit different levels of linguistic structure.