Rule reminder
Impersonal verbs in the conditional express hypothetical necessity, advisability, or probability. Bisognerebbe = one should / it would be necessary. Converrebbe = it would be advisable. Basterebbe = it would be enough. Sembrerebbe = it would seem. Varrebbe la pena = it would be worth it.
Completa: '___ che tutti collaborassero — il lavoro sarebbe finito in tempo.' (bastare — conditional + congiuntivo)