This paper aims to investigate the decline and demise of the English BE perfect and to discuss the usage of English BE perfect relics in Present-day English (PE). Given the ambiguity or a heavy functional load of the construction BE plus a past participle, including BE perfect, the decline and demise of the BE perfect resulted from first, language strategy to avoid ambiguity, second, the avoidance of heavy functional load, and finally, counterfactuality, followed by the replacement of BE perfect by HAVE perfect. HAVE perfect almost completely dominated by the turn of the 19th century. Here, we find the change of the feature system of the BE perfect with the dropping of the feature [+UNACCUSATIVE], implying that the “old” unaccusative predicates, which took BE auxiliary, may take HAVE now. Another recent significant factor of the disappearance of the BE perfect is that when BE perfect had no distinctive functional load from HAVE perfect, it disappeared from the English language. The PE relics of the English BE perfect, like be gone, done, finished, changed, and so on, have their own distinctive functional load that is different from that of their HAVE perfects, respectively, indicated by syntactic-semantic features [±BEING] and [±STATIVITY].