Masking

it is a concept of creating a animation
1.creat a stage of any size nd assign the black color as background.
2.insert a shape of rectangle with darck grey color.
3.type a text wit white color.
4.all da above must be on layer's and use f5 to keep da layer's.
5.insert new layer and add ashape on da 1st frame.
6.convert the shape to symbol using f8.
7.now selest the target frame f6.
8.select da layer nd right click on da layer nd apply creativemotion.
9. right click on layer nd apply mask.