ἄνδρες, καλῶς ἔσται, ἢν θεὸς θέλῃ
‘’ (Xen. Anab. 2.3.19)
Relatively infrequently adverbs serve as predicate NP.
ἔνθα διαγνῶναι χαλεπῶς ἦν ἄνδρα ἕκαστον
It was difficult to know every man there.
Hom. Il. 7.424