As the standard conditional particle of New Testament Greek, ei introduces the protasis ('if'-clause) of conditional sentences across every type: simple conditions of fact (ei + indicative), contrary-to-fact conditions, and mixed forms. It appears over 500 times, making it one of the most frequent function words in the NT. A significant secondary pattern is the combination ei me ('if not'), which functions as an exceptive marker meaning 'except' or 'unless,' as in Matt 11:27, 'no one knows the Father except (ei me) the Son.' Spanish distinguishes the two uses clearly: 'si' for conditional vs. 'sino' for exceptive.