Although John never worries. Jane promises to address the problem of limited downtown parking. If she is elected to the city council. Turn the fragment into a sentence. Power tends to corrupt, absolute power corrupts absolutely.
Power tends to corrupt, moreover, absolute power corrupts absolutely.
He left the game, he's coming back. He left the game, however, he's coming back. Use a semicolon. Make the clauses into separate sentences. He left the game, but he's coming back.