Keywords: galaxies:active - galaxies:nuclei - galaxies:emission lines - galaxies:Seyfert

1. INTRODUCTION

2. PARENT SAMPLES OF SDSS PIPELINE CLASSIFIED TYPE-2 AGN

3. LONG-TERM CSS PHOTOMETRIC VARIABILITIES OF THE SDSS TYPE-2 AGN

4. SPECTROSCOPIC RESULTS OF THE 156 TYPE-2 AGN WITH LONG-TERM VARIABILITIES

5. DISCUSSIONS

6. SUMMARIES AND CONCLUSIONS