A simple sentence such as John loaded the software contains just one independent clause. A compound sentence contains two independent clauses : John loaded the software, and Mary installed the hard drive. A complex sentence contains both an independent clause and a dependent clause. For example, After the installation was complete, the computer was rebooted is an example of a compound sentence. Finally, a compound-complex sentence contains at least two independent clauses and one dependent clause. Because they are so long, compound-complex sentences should be used sparingly. After the installation was complete, the computer was rebooted, and the IT department successfully completed the upgrade is an example of a compound-complex sentence.