If the query string will only ever be of the form "?number", then you can use:
if ($_SERVER['query_string'] == "one") {
echo "page one content";
} elseif ($_SERVER['query_string'] == "two") {
echo "page two content";
} else {
echo "default content";
}
Equivalently, with a switch instead:
switch ($_SERVER['query_string']) {
case "one":
echo "page one content";
break;
case "two":
echo "page two content";
break;
default:
echo "default content";
}
If the query string could contain more than just that value (e.g., "?one&x=123"), then you could do something like:
if (isset($_GET['one'])) {
echo "page one content";
} elseif (isset($_GET['two'])) {
echo "page two content";
} else {
echo "default content";
}