Linked forms in which the existence of "koso" caused the sentence to end with a classical imperfective form were more and more often accompanied by an adversative conjunction but remained for a longer time than the linked forms with an attributive form.
已然形で結ぶ「こそ」の係結びも、逆接の接続助詞を伴ったものが増えてきたが、連体形係結びに比べて後代まで残った。