Main clauses express a complete thought and appear in compound, complex and compound-complex sentences. Therefore, the correct answer is all of the above. A compound sentence is made up of two independent clauses which are joined by a coordinating conjunction. A complex sentence is made up of an independent clause and a dependent clause which are joined by subordinating conjunction. A compound-complex sentence is made up of two or more independent clauses and one or more dependent clauses.
My favorite Dr. Seuss book is Oh The Places You Will Go. I love this book because it was one of the first Dr. Seuss books I read. It also brings back memories.
