Adding Movie on Stage for a period of time

I have a relatively simple question. I am new to AS3 and would like to add a movieclip to the stage (on a FrameEnterEvent) for only a few seconds.

I know how to add and remove the movie clip but how do a specify the period of time I want the movie clip to appear on stage?

Help!

Use the Timer Class. Here is a tutorial: http://www.republicofcode.com/tutorials/flash/as3timer/

Thanks. I'll try it.