The clause shown in parentheses before "they had dinner" is a subordinate clause, specifically an adverbial clause. It provides additional information about the timing or condition related to the main clause. This type of clause typically cannot stand alone as a complete sentence.
Noun
adverb - Brittany buttonz :D
The clause in parentheses, "when we finish dinner," is a subordinate or dependent clause. It cannot stand alone as a complete sentence and provides additional information about the timing of the action in the main clause. The clause begins with the subordinating conjunction "when," which introduces the condition under which the main action will occur.
Adverb
Adverb
Adverb
Adverb clause
adjective
adverb
adverb
adverb
adverbial clause