The research problem is crystallized around whether IEFL can: 1. reduce finite relative clauses, functioning as postmodifier, to non-finite ones in a correct way. 2. realize the eliminated items and changed verbs after the reduction process. 3.differentiate between nominal relative clauses and non-finite postmodifying clauses used adjectively. In the light of the problem, the following hypotheses are drawn: 1. The learners face more difficulties in reducing finite relative clauses that have lexical verbs than those having be verb forms. 2. Iraqi EFLs cannot distinguish between ing and to-infinitive nominal clauses on the one hand and their equivalent postmodifying non-finite forms used adjectively on the other.