添加了h3

new.txt

@@ -3,5 +3,6 @@
   <p >hello world <p>
   <h2> this is a new world!</h2>
   <h1> this is a new world! ok I know it</h1>
+ <h3> this is a new world! ok I know it</h3>
 </html>
 </body>