Complex sentence: It was introduced in September 2000 (with the first AS-level examinations held in Summer 2001 and A2 examinations the following year), an A-level now consists of six units studied over two years.
Split into simpler sentences: It was introduced in September 2000 (with the first AS-Level examinations held in Summer 2001 and A2 examinations the following year). An A Level now consists of six units studied over two years.