1. Use commas to separate independent clauses when they are joined by any of these seven coordinating conjunctions: and, but, for, or, nor, so, yet.
The game was over, but the crowd refused to leave.
The student explained her question, yet the instructor still didn't seem to understand.
Yesterday was her brother's birthday, so she took him out to dinner.
from:
owl.purdue.edu/redirect.html
