$dynamicsubstring1 = "double-quoted substring01";
$dynamicsubstring2 = "double-quoted substring02";
$str = sprintf('This is a string with "%s", and "%s" inside.', $dynamicsubstring1, $dynamicsubstring2);
echo $str;
/*
run:
This is a string with "double-quoted substring01", and "double-quoted substring02" inside.
*/