Rule reminder

Common errors in cleft sentences: (1) Using 'chi' instead of 'che' with a specific focused element. (2) Failing to agree 'essere' with the focused element in number. (3) Using wrong word order (putting 'che' before the focused element). (4) Using 'cosa' instead of 'che' as the connector. (5) Forgetting 'a' before the infinitive in the 'essere + a + infinitive' construction. (6) Using a subordinating conjunction ('perché', 'quando') instead of 'che' in a standard cleft.