各位这句英文警告是什么意思？看不懂啊
Warning: date() [function.date]: It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'UTC' for '8.0/no DST' instead in D:\AppServ\www\PHPMailer\class.phpmailer.php on line 2387
