Complex sentence: Her television appearances have occurred in every decade from the 1960s thru the 2000s, at first as one-time appearances in comedies and dramas, then as a regular on "Guiding Light" (Janet Mason Morris, 1969-1975).
Split into simpler sentences: Her television appearances have occurred in every decade from the 1960s thru the 2000s. As a regular on "Guiding Light" (Janet Mason Morris, 1969-1975).