Selecting Multiple Clips
The Shift and Command keys allow you to select multiple clip items in the Timeline,
either contiguous or noncontiguous.
To select multiple noncontiguous clip items:
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Hold down the Command key while selecting the desired clip items using either the
Selection tool or the Group Selection tool.
You can also Command-click a specific item again to deselect it.
To select multiple contiguous clip items with the Selection tool:
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Select a clip item, then hold down the Shift key and select another clip item farther
down on the Timeline. All of the clip items between the two are selected.
 If you select two clip items on the same track, only the items on that track (and items
linked to items on that track) are selected.
 If you select a clip item on one track and another clip item on a different track, all clip
items between those two tracks are selected as well.
You can also select a range of contiguous clip items, and then select additional
noncontiguous clip items using a combination of the instructions above.