He likes running and to play soccer.Here, both elements of the series perform the same grammatical function: direct object of the verb likes. But they appear in different forms, one as an ‑ing verb (present participle) acting as a noun (that is, a gerund), the other as a to verb (infinitive) acting as a noun. To follow the rule, we would write:
He likes running and playing soccer.Previous: 1. Coordinating Conjunctions Next: Serial-Comma Rule - Red, White, and Blue
He likes to run and to play soccer.