Other Uses of Εἰ 655 After expressions of doubt or inquiry, εἰ with the indicative (rarely ἐν with the subjunctive) becomes an indirect question. In such clauses εἰ (or ἐν) may sometimes be translated if, but more often whether:

Εἰ μὲν δὴ δίκαια ποιήσω οὐκ οἶδα whether I shall be doing right I do not knοw. AN. I. 3, 5. εἰ ξυμπονήσεις καὶ ξυνεργάσῃ σκόπει see whether thou wilt work with me and share the deed. S. AN. 41.