title: How to replace phrase in php?
body: <p>I tried replace phrase in php by function str_replace. it's only replace two word. Ex: <code>str_replace("noi that","noi thiet",$subject)</code>.      </p>
  
  <p>I want replace phrase > 2 word. Ex: str_replace("noi that Mien Nam","noi that Mien Bac", $subject). But it not true. Can you help me? Thanks you      </p>