Conjunctions join words, phrases, or clauses. Greek has coordinating and subordinating conjunctions.
Coordinating (join equals): • καί (and), τε...καί (both...and) • ἀλλά (but), δέ (but, and) • ἤ (or), ἤ...ἤ (either...or) • γάρ (for, because - postpositive) • οὖν (therefore - postpositive)
Subordinating (introduce dependent clauses): • ὅτι, ὡς (that, because) • ἵνα, ὅπως (in order that) • εἰ, ἐάν (if) • ὅτε, ἐπεί (when, since) • πρίν (before, until)
Postpositive conjunctions (δέ, γάρ, οὖν) never begin a clause.