Complex sentence: By the 1970s, his work had also come to exert a considerable influence on philosophy, and a poll conducted by Minnesota State University found "Syntactic Structures" to be the single most important work in the field of cognitive science.
Split into simpler sentences: By the 1970s, his work had also come to exert a considerable influence on philosophy. A poll conducted by Minnesota State University found "Syntactic Structures" to be the single most important work in the field of cognitive science.