After a bear cub survived a forest fire in 1950 he became known as smokey and he lived in the national zoo for many years what is the sentence structure in the sentence

Taking into account its structure, this is a compound-complex sentence.

"After a bear cub survived a forest fire in 1950 he became known as Smokey and he lived in the national zoo for many years" is a compound-complex sentence because it contains two independent clauses ("he became known as Smokey" and "he lived in the national zoo for many years") and one dependent clause ("after a bear cub survived a forest fire in 1950"). The two independent clauses are joined by the coordinating conjunction "and" and the dependent clause is introduced by the subordinating conjunction "after". A compound-complex sentence is a combination of a compound sentence, which contains two independent clauses, and a complex sentence, which has a dependent clause joined to an independent clause.