Apple Final Cut Express 4 - Manual (Page 285)

Chapter 20 Creating Subclips 285
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7 Choose Modify > Make Subclip.
Note: If you gave your markers new names, your subclips will use them.
The subclips appear in addition to the original clip with the markers. You can rename the
subclips, if you want. You can review the subclips, deleting any clips you might not need.
All of the material
between the markers
you selected should now
appear as subclips.