Simple
A complex sentence have one or more independent clauses
A compound-complex sentence has to have at least three independent clauses.
I walked my dog to the dog park.
Coffee is good, but not without creamer.
Why is this not a simple sentence?
I walked and played fetch with my dog at the dog park.
A dependent clause needs an independent clause to make a complete sentence.
When it is cloudy, I like to sit outside and sometimes I read a book.
The girl skipped to the park.
She ate a popsicle there.
If you make pancakes, you should serve them with syrup, or else they will be too dry.
Even though she prefers to play soccer, she tried baseball, and had fun doing it.