Complex sentence: He made his first-team debut as a substitute against Liverpool on 1 February 1975, and was a regular in the latter half of the 1975--76 and throughout the 1976--77 seasons.
Split into simpler sentences: He made his first-team debut as a substitute against Liverpool on 1 February 1975. Ross was a regular in the latter half of the 1975--76 and throughout the 1976--77 seasons.