Here's why:
* Simple sentences contain one independent clause, which means they express a complete thought on their own.
* Subordinate clauses are dependent clauses, meaning they cannot stand alone as a complete sentence. They rely on an independent clause for their meaning.
Example:
* Simple Sentence: The dog barked loudly. (One independent clause)
* Sentence with a Subordinate Clause: The dog barked loudly because it was hungry. (Independent clause + dependent clause)
Let me know if you'd like more examples!