_root. with wait

hello guys

i got this code:

onClipEvent (enterFrame) {
if (!loaded && this._url != _root._url) {
if (this.getBytesLoaded() == this.getBytesTotal()) {
loaded = true;
_root.transition.gotoAndPlay(“opening”);
}
}
}

and than i would like to load another image
and i put this code…
it works…
but i would like to put all these codes in the same frame, and put a time between every image…
for example…

//wait 20 seconds//
_root.section = “images/kualkosadi.jpg”;
_root.transition.gotoAndPlay(“closing”);
//wait 20 seconds//
_root.section = “images/colors.jpg”;
_root.transition.gotoAndPlay(“closing”);

etcc…

how can i do an actionscript who says to wait 20 second?

bye bye