Question on Smyth 1784

τίς γὰρ ἂν ᾠήθη ταῦτα γενέσθαι; (for who would have expected these things to happen?)

The sentence seems wrong me, ᾠήθη is in the passive, for the translation to be correct, it should have been ᾤετο instead. I don’t see what I am missing. As it seems now the sentence seems to mean “For who would have been expected these things happen?” which doesn’t make sense.

οἴομαι uses the passive forms in the aorist and future with no change in meaning. In fact, calling these θη forms ‘passive’ is a bit of a misnomer, as in many cases there isn’t really a passive meaning involved. See chapter 35 of the Cambridge Grammar (section 35.26 for this particular verb).