Don’t use a comma to separate an introductory independent clause from a following dependent clause.
I live in a small village, because I can get into the mountains very quickly.
(independent clause/I live in a small village)
I live in a small village because I can get into the mountains very quickly.
If the dependent clause comes first, a comma is needed.
- Because I can get into the mountains very quickly, I live in a small village.
(dependent clause/Because I can get into the mountains very quickly)
