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interrogative: P. and V. τί; see why.
relative, for which reason: P. and V. ἀνθ' ὧν, P. διό, διόπερ, ὧν ἕνεκα, V. ὧν οὕνεκα.
therefore, before imperatives: P. and V. πρὸς ταῦτα (Thuc. 4, 87; Ar., Nubes 990 and 1433), V. πρὸς τάδε; see therefore.