To intercept the PHP specified string code, how to solve

To intercept the PHP specified string code
Has the following HTML string:
Aaaa
bbbb
Cccc
dddd

To output the following:
Aaaa
dddd

That is, delete the middle of two
The previous content and
The simple code, because the output is also HTML, not array mode.
------Solution--------------------

$s = ' aaaa
bbbb
Cccc
dddd
';
echo preg_replace ('/
\w+/', ', $s, 2);

Aaaa
dddd

------Solution--------------------
1

echo preg_replace ('/
[^<]+/', ', $s, 2];

2

echo preg_replace ('/\ (. +?\)/', ', $s);

------Solution--------------------

echo Preg_replace_callback ('/

function foo ($m) {
     return Strpos ($m [0], ' (')!== false? Preg_replace ('/\ (. +?\)/', ', $m [0]): ';     
}

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