I need help about the Be sure to delete all trailing comment tags, i.e. -->

Tell us what’s happening:

I can not understand this means" Be sure to delete all trailing comment tags, i.e"

Your code so far

<h1>Hello World</h1>
<p>Kitty ipsum dolor sit amet, shed everywhere shed everywhere stretching attack your ankles chase the red dot, hairball run catnip eat the grass sniff.</p>
<!--uncomment h1,h2,and p elemenst-->

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User Agent is: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:68.0) Gecko/20100101 Firefox/68.0.

Link to the challenge:

you were tasked with deleting the comment tags to make the three elements visible
the three elements are visible, but you still have all the comment tags, and more have been added
why do you have all those comments in your code?