What is a compound-complex sentence?
A compound-complex sentence is made up of two or more independent clauses and at least one subordinate clause.
Examples
1. Frances Cabrini, who was the first American citizen to be declared a Catholic Saint, was born in Italy, but she became an American in 1909.
Independent clause: Francis Cabrini was born in Italy
Independent clause: she became an American citizen in 1909
Subordinate clause: who was the first American citizen to be declared a Catholic Saint (adjectival clause)
2. She organized some of her sisters into a new order, and they were assigned to work in America by the pope, who was Pius XIII.
Independent clause: She organized some of her sisters into a new order
Independent clause: they were assigned to work in America by the pope
Subordinate clause: who was Pius XIII (adjectival clause)