1. With the imperative.
2. In clauses with εἰ, ἐά_ν (exceptions, cross2698).
3. With the subjunctive, except after μή
4. With the optative, except after μή
5. With the infinitive, except in indirect discourse.
6. With participles when they have a conditional or general force.
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].