Types of Sentences

A simple sentence consists of one single main clause:
The dog was chasing the cat.

A compound sentence consists of two or more co-ordinated main clauses: Martha sang, and Johann played the piano.
Joon Hui likes Japanese food, but Mila can't stand it.

A complex sentence contains at least one main clause and one subordinate clause:
Jia Hui went home because she was tired.


One More Time!

simple (consisting of one clause)
compound (consisting of two co-ordinated main clauses)
complex (containing at least one subordinate clause)
Examples:
Simple: I was reading the newspaper.

Compound: I read the newspaper, but nothing caught my interest.

Complex: I was reading the newspaper that I subscribe to.
I was reading the newspaper while I was having breakfast.
I was reading the newspaper while having breakfast.