Put a comma before a conjunction that joins two complete thoughts.
You should know this one pretty well by now!

Abby and Paige are cheerleaders.
+
They are also good students.
=
Abby and Paige are cheerleaders, and they are also good students.

Ruth borrowed Emilie's CD.
+
She didn't tell Emilie.
=
Ruth borrowed Emilie's CD, but she didn't tell Emilie.

We can go to the park.
+
We can go out to eat.
=
We can go to the park, or we can go out to eat.

Do you need to try the quiz again?

Move on to Rule 2.