What is the difference between a simple and a complex sentence?

Sure, here's the difference between a simple and a complex sentence:

Simple Sentence:

• A single independent clause.
• Contains a subject and a predicate.
• Cannot stand alone as a complete thought.

Example:

The dog barked.

Complex Sentence:

• Contains two or more independent clauses.
• Each clause contains a subject and a predicate.
• Can stand alone as a complete thought.

Example:

The dog barked at the mailman. He was carrying a package.

In simple sentences, the subject and predicate are connected by a conjunction, while in complex sentences, the subject and predicate are connected by a conjunction or a coordinating conjunction.