Complaints must be made through the proper channels.
投诉必须通过正当途径进行。
英语解释：a method or system that people use to get information, to communicate, or to send sth somewhere 途径；渠道；系统:
,
Complaints must be made through the proper channels.
投诉必须通过正当途径进行。
英语解释：a method or system that people use to get information, to communicate, or to send sth somewhere 途径；渠道；系统:
,
