学界对构式范畴的争议源于没有厘清其理论／ 操作层面，本文提出基于频次的认知固化可以作为构式的操作界定。认知固化的渐变性、层级性、动态性对应构式的原型性、抽象度、动态性。通过对英语本族语者的关系代词取舍开展基于条件概率的共现词分析发现：1）隐性／ 显性关系代词从句呈现基于条件概率的认知固化，可以被界定为构式；2）隐性关系代词从句比显性关系代词从句更加靠近具体词语层面，认知加工负载更小。

The dispute, in regard to construction delineation, largely originates from the blurring distinction of theoretical and operational conceptions. This study claims that constructions could be operationally delineated as the frequency-based form-meaning entrenchment which is verified through examining conditional probability among linguistic structures. Entrenchment is in line with constructions with regard to its gradualness, gradedness, and dynamicity. A conditional probability based collexeme analysis of relativizer omission by native speakers of English has revealed that a) relativizer omission should be classified as constructions on grounds of their entrenchment retrieved through conditional probability; b) distinct discrepancies could be verified between implicit/explicit relativizer constructions with the former geared towards concrete lexical dimension, thus requiring a lower cognitive load.