Fill a square?

programming flash
1

How can I fill a square made with:

createEmptyMovieClip("Line",1);
Line.lineStyle(1,0x000000,100);
Line.moveTo(20, 20);
Line.lineTo(30, 20);
Line.lineTo(30, 30);
Line.lineTo(20, 30);
Line.lineTo(20, 20);

I have tested to write


 Line.beginFill(0x00ff00, 100);
 Line.endFill();

after it but it dident happen anything.
Please help me =)