477 Such a sentence may be introduced by εἴθε or εἰ γάρ, in poetry by εἰ alone (cp. 470):

Eἴθε μήποτε γνοίης ὅς εἶ mayst thou never learn who thou art. S. OT. 1068. εἰ γὰρ ἐν τούτῳ εἴη may it only depend on that! PR. 310 d.