Ask a regular expression and how to exclude it <br>

How can I exclude the regular expression & lt; br & gt; PHPcode & lt ;? Php $ str = 'IMG my B has 110www & lt; br & gt; has 110110 hao'; echopreg_replace ('/(img | 110 | B)/I', & quot; & lt; B & gt ;\1 {1} & lt;/how to exclude a regular expression

PHP code

  
  110110 OK '; echo preg_replace ('/(img | 110 | B)/I ',"\ $ {1}", $ Str);?>

The purpose is to display the specified characters in bold. how can this problem be ruled out?
, Do not let
Bold.


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Echo preg_replace ('/(img | 110 | B \ B)/I '," \ $ {1}", $ Str );
Or
Echo preg_replace ('/(img | 110 | B (?! R)/I '," \ $ {1}", $ Str );

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?! R
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PHP code

'/(?
  ------ Solution --------------------
If you need to consider the complex points, the regular expression is slightly more complex. pay attention to the img, 110, B in the html tag of the tag.

  
  

   
   
PHP code
   
   
$ Str = 'I img I B have 110www
110110 OK '; echo preg_replace ('#(? = [^>] * (? = <| $) (Img | 110 | B) # is ','\ 1', $ Str );