Rule reminder
In formal writing, consecutive clauses often use 'tale...che', 'al punto che/da', and 'talmente...che'. The structure 'così...che' is also acceptable but slightly less formal. Avoid colloquial alternatives like 'quindi' or 'per cui' when a proper consecutive is expected.
La crisi economica era _____ grave _____ il governo dovette intervenire d'urgenza.