Complex sentence: Play must not exceed 31, so a player who cannot lay a card without bringing the total above 31 passes by saying "Go"; the other players continue to lay cards in turn without exceeding 31 until no cards can be played.
Split into simpler sentences: Play must not exceed 31, so a player who cannot lay a card without bringing the total above 31 passes by saying "Go". The other players continue to lay cards in turn without exceeding 31 until no cards can be played.