Complex sentence: Glass founded the Philip Glass Ensemble, with which he still performs on keyboards, and has written numerous operas and musical theatre works, ten symphonies, eleven concertos, solo works, chamber music including seven string quartets and instrumental sonatas, and film scores.
Split into simpler sentences: Glass founded the Philip Glass Ensemble, with which he still performs on keyboards. He has written numerous operas and musical theatre works, ten symphonies, eleven concertos, solo works, chamber music including seven string quartets and instrumental sonatas, and film scores.