The conjunction comma is used with a conjunction such
as and, but, or so to separate two main clauses.
The choice of either and or but or another conjunction
depends on the relationship you want to convey between two
main clauses. However, be sure to include a conjunction-a
conjunction comma without a conjunction cannot do its job
The attorney filed the appeal today, but the judge
will not make a decision on it until next week.
The material used in our suit coats is the very best
available, and we guarantee you will be satisfied with every
coat you purchase from us.
I scored 97 percent on my final exam, so I think
I will probably get an A in the class.