Rule reminder

Occorre (it is necessary/one must) + infinitive: 'Occorre portare il passaporto.' Followed by an infinitive, occorre stays 3rd person singular like bisogna. But when followed by a plural noun as its subject, occorrere agrees in number (occorrono due ore). It is slightly more formal than bisogna. Imperfect: occorreva. Future: occorrerà. Conditional: occorrerebbe/occorrerebbero.