Apple Final Cut Pro 7 - Manual (Page 689)

2 Select the Roll tool from the Tool palette (or press the R key).
3 Drag the audio edit point to the right so that the entire word plays at the end of the first
clip.
Now when you play through this cut, you can hear all of the words the first person is
saying, and then the second person’s reply.
689 Chapter 43 Audio Editing Basics