Complex sentence: Beginning in the early 20th century, secular education became more widespread, and in the PRC era, Uyghurs may have a choice from two separate secular school systems, one conducted in their own language, and one offering instructions only in Chinese.
Split into simpler sentences: Beginning in the early 20th century, secular education became more widespread. Early in the PRC era, Uyghurs may have a choice from two separate secular school systems, one conducted in their own language, and one offering instructions only in Chinese.