Here's a breakdown:
* Main clause: A main clause has a subject and a verb and can stand alone as a complete sentence.
* Subordinate clause: A subordinate clause also has a subject and a verb, but it cannot stand alone as a complete sentence. It depends on the main clause for its meaning.
* Compound sentence: A compound sentence joins two or more main clauses together using a coordinating conjunction (like "and", "but", "or", "so", "yet", "for", or "nor").
Example:
* Main clause: The sun is shining.
* Main clause: The birds are singing.
* Compound sentence: The sun is shining, and the birds are singing.