Simple Sentences:
* I stayed home because I was sick.
* The dog barked because it was hungry.
* We went to the park because it was a beautiful day.
Complex Sentences:
* Because it was raining, we decided to stay inside.
* She was late because her car broke down.
* He was happy because he got a promotion.
With Clauses:
* I went to the store because I needed milk.
* We ate lunch because we were hungry.
* He ran quickly because he was being chased.
To Explain a Reason:
* "Why are you sad?" "Because my friend moved away."
* "Why did you choose that shirt?" "Because I like the color."
* "Why are you smiling?" "Because I'm happy!"
Remember that "because" is used to introduce the reason for something. It's usually followed by a clause that explains the cause.