$text = '<p class="sinif"><a href="#"><span class="c1">değer1</span><span class="c2">değer2</span></a></p>';

preg_match('#<p class="sinif"><a href="#"><span class="c1">(.*?)</span><span class="c2">(.*?)</span></a></p>#si',$text,$dizi);

$deger1 = $dizi[1];
$deger2 = $dizi[2];

echo $deger1 . ' - ' . $deger2.'<br>';