刚才给出了一个如何实现的示例：

$today_date      = new DateTime( date( \'Y-m-d\', strtotime( \'today\' ) ) );
    $register_date  = get_the_author_meta( \'user_registered\', get_current_user_id() );
    $registered = new DateTime( date( \'Y-m-d\', strtotime( $register_date ) ) );
    $interval_date   = $today_date->diff( $registered );
        if( $interval_date->days < 31 ) {
            echo \'With us \' . $interval_date->format(\'%d days\');
            }
        elseif( $interval_date->days < 365 ) {
            echo \'With us \' . $interval_date->format(\'%m months %d days\');
            }
        elseif( $interval_date->days > 365 ) {
            echo \'With us \' . $interval_date->format(\'%y years %m month %d days\');
            }