A compound-complex sentence is a sentence made from two independent clauses and one or more dependent clauses. The compound-complex sentence is one of the four basic sentence structures including simple sentences, compound sentences and complex sentences.
Compound-complex sentences are used in various forms of analytical writing, especially in academic writing. They are also referred to as complex-compound sentences. In compound-complex sentences, the subordinate clause can be part of an independent clause.
Though the compound-complex sentence is commonly used in English, students may have a great deal of trouble writing them if they have not mastered the other three basic sentence structure.