$source=file( "name_file.txt" );
$serchWord= "word" ;
foreach($source as $str){
  if(preg_match( "/" .$serchWord. "/Ui" ,$str){
   $arrayStr=preg_split( "/ /" ,$str);
   for($pos= 0 ;$pos< 3 ;$pos++){
    echo $arrayStr[$pos]. " " ;
   };
   echo  "\n" ;
  };
};