Answer:
Complex sentence
Step-by-step explanation:
A COMPLEX SENTENCE contains two clauses: an independent clause and a dependent or subordinate clause. The sentence "We never saw Sarah, the girl with our movie tickets" is a complex sentence having first an independent clause: "We never saw Sarah" and then a dependent clause: "the girl with our movie tickets" separated by comma. A complex sentence has its two clauses separated by a comma especially when a dependent clause comes first before the subordinate clause. The independent clause can stand alone but the subordinate clause, though it contains both a subject and a predicate cannot stand alone.
A complex sentence is similar to a compound sentence but a compound sentence contains two independent clauses.