X-PuDu at SemEval-2022 Task 7: A Replaced Token Detection Task Pre-trained Model with Pattern-aware Ensembling for Identifying Plausible Clarifications

This paper describes our winning system on SemEval 2022 Task 7: $\textitIdentifyingPlausibleClarificationsofImplicitandUnderspecifiedPhrasesinInstructionalTexts$. A replaced token detection pre-trained model is utilized with minorly different task-specific heads for SubTask-A: $\textitMulticlassClassification$ and SubTask-B: $\textitRanking$. Incorporating a pattern-aware ensemble method, our system achieves a 68.90 accuracy score and 0.8070 spearmans rank correlation score surpassing the 2nd place with a large margin by 2.7 and 2.2 percent points for SubTask-A and SubTask-B, respectively. Our approach is simple and easy to implement, and we conducted ablation studies and qualitative and quantitative analyses for the working strategies used in our system.