PHP中的HTML <pre>自动换行不起作用

I've been working on a forum, and I've made everything work as it, and I tried wrapping to see if it works, basically that part of the code looks like this before the PHP I got some HTML style:

<style>
    pre {
        white-space: pre-wrap; 
        white-space: -moz-pre-wrap;
        white-space: -pre-wrap;
        white-space: -o-pre-wrap;
        word-wrap: break-word;    
        font-size: 20px;
        margin: 0% 8% 0px 8%; 
    }
</style>

And then after a bunch of MySQL things

echo '<table style="height: 21px;" width="100%">';
while($forumcomrow=mysqli_fetch_array($forumcomres))
{
    echo '<tr><td>some text</td><td><pre>Some Very Long Text From Mysql </pre></td></tr></br>';
}
echo '</table>';

I removed everything and just left the style for it and the echo for the table, when I echo just the pre tag, it wraps it at the end of the screen, but as soon as I put it in a table (size doesn't matter, even if I put the width of the table to 5px) it still goes 10 miles off the screen until it starts wrapping.

This is what happens:

On the picture above you can see one part of it, but the text goes off screen about 5x the length you can see on there, and only then starts wrapping

I have figured out what's giving it a problem, it will wrap the text if it has spaces ("aaaa aaa aaa aa aa") but if its one long word ("aaaaaaaaa") it won't wrap it, I don't know how to fix it, I've just figured out whats causing the problem.

It is because of <br> tag at the end, I have faced the same problem some time ago. <br> get applied first for every time and then table gets wrapped.

Remove <br> at the end

echo '<tr><td>some text</td><td><pre>Some Very Long Text From Mysql </pre></td></tr>';

and then it will work perfectly fine.