What do you mean by this English warning? You cannot understand

What does this warning mean? Do not understand Warning: & nbsp; date () & nbsp; [function. date]: & nbsp; It & nbsp; is & nbsp; not & nbsp; safe & nbsp; to & nbsp; rely & nbsp; on & nbsp; the & nbsp; what does this warning mean by syst? You don't understand.
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

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Add date_default_timezone_set ("PRC") to the page header.
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You can try to modify the timezone value in the php. ini configuration file.