Simple Sentences
(independent clauses – each sentence stands on its own)
The apple fell from the tree.
The big, beautiful bird sang a lovely song.
Compound Sentences
(two sentences combined with a comma and a conjunction)
The big, beautiful bird sang a lovely song, and the apple fell from the tree.
The apple fell from the tree, but the big and beautiful bird sang a lovely song.
Complex Sentences
(one sentence combined with a dependent clause, which could not stand on its own)
The beautiful bird sang a lovely song since the apple fell from the tree.
Since the apple fell from the tree, the beautiful bird sang a lovely song.