text: public override int Previous(){if (text.Index == text.BeginIndex){return Done;}else{if (0 == sentenceStarts.Length){text.SetIndex(text.BeginIndex);return Done;}if (text.Index == text.EndIndex){text.SetIndex(sentenceStarts[currentSentence]);}else{text.SetIndex(sentenceStarts[--currentSentence]);}return Current;}}