What are predicative clauses and adverbial clauses?

Predicative clause, use clause as predicative. Simple understanding is the clause after the verb in the main sentence.

The problem is that we have no tickets.

An adverbial clause is an adverbial clause. Simply understood as: the main structure of the clause (subject-predicate-object; The main system table is complete, and the verb time of the main sentence is explained by clauses; Location; Conditions, etc.

When we broke in, we found that the carpet was on fire.