Complex sentence: During this era, and after having taught in numerous jazz clinics at high schools and universities, Slater was regarded as a leading educator in jazz as evidenced by his appointment as one of the two directors of the two 1979 Delaware All-State Jazz Ensembles.
Split into simpler sentences: During this era, and after having taught in numerous jazz clinics at high schools and universities, Slater was regarded as a leading educator in jazz. He was one of the two directors of the two 1979 Delaware All-State Jazz Ensembles.