<?php
$content = '
hello world
hello
<!-- wp:paragraph -->
<p></p>
<!-- /wp:paragraph -->
<!-- wp:paragraph -->
<p></p>
<!-- /wp:paragraph -->
<!-- wp:paragraph -->
<p></p>
<!-- /wp:paragraph -->
aaa
';
//$text = str_replace(array("\n"." "."\n", ' ', ' ', ' '), '', $text);
$content = str_replace(array("<!-- wp:paragraph -->"."\n"."<p></p>"."\n"."<!-- /wp:paragraph -->", '<!--[if gte mso 9]>-->', '<p></p>', '<h2></h2>'), '', $content);
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