wordwrap php使用wordwrap重新格式化文本段落

<?php
$string = "TRADING ON MARGIN POSES ADDITIONAL 
RISKS AND IS NOT SUITABLE FOR ALL 
        INVESTORS. 
A COMPLETE LIST OF THE RISKS ASSOCIATED WITH MARGIN TRADING IS
AVAILABLE IN THE MARGIN RISK DISCLOSURE DOCUMENT.";
$string = str_replace("\n", " ", $string);
$string = str_replace("\r", " ", $string);
print(wordwrap($string, 40)."\n");
?>

上面的代码返回如下结果

TRADING ON MARGIN POSES ADDITIONAL
RISKS AND IS NOT SUITABLE FOR ALL
INVESTORS. A COMPLETE LIST OF THE
RISKS ASSOCIATED WITH MARGIN TRADING IS
AVAILABLE IN THE MARGIN RISK DISCLOSURE
DOCUMENT.