在正式的邮件、书信、通告中，如不能确定具体收件人的身份或姓名，则可以用 “To whom it may concern” 来开头，它相当于汉语正式信件中的表达 “敬启者”、 “致有关人士”。比如，如果一位顾客想给一家公司写投诉邮件，则可以用 “To whom it may concern” 来称呼售后服务部门的工作人员。在正式信函中，“To Whom It May Concern” 中的每个单词的首字母往往会大写。
例句
1.
To Whom It May Concern,
I am writing to complain about a product I recently purchased. Not only had it obviously been previously used, it also had no instruction manual.
致有关人士：
我想对近期购买的一件产品进行投诉，特此致信。该产品不仅已被使用，而且缺少使用说明书。
2.
To Whom It May Concern,
I am writing to confirm that Miss Ju was employed as a Sales Manager by ABC Trading from 2nd September 2008 to 14th October 2012.
敬启者：
此信确认鞠女士于2008年9月2日至2012年10月14日在 ABC 贸易公司担任销售经理一职。
3.
To Whom It May Concern,
I am writing to express my interest in attending the Annual Golf Conference on 14th October and would like some more information on the prices of tickets.
敬启者：
本人有意参加于10月14日举办的年度高尔夫大会，特此致信了解更多有关票价的信息。
例句
1.
To Whom It May Concern,
I am writing to complain about a product I recently purchased. Not only had it obviously been previously used, it also had no instruction manual.
致有关人士：
我想对近期购买的一件产品进行投诉，特此致信。该产品不仅已被使用，而且缺少使用说明书。
2.
To Whom It May Concern,
I am writing to confirm that Miss Ju was employed as a Sales Manager by ABC Trading from 2nd September 2008 to 14th October 2012.
敬启者：
此信确认鞠女士于2008年9月2日至2012年10月14日在 ABC 贸易公司担任销售经理一职。
3.
To Whom It May Concern,
I am writing to express my interest in attending the Annual Golf Conference on 14th October and would like some more information on the prices of tickets.
敬启者：
本人有意参加于10月14日举办的年度高尔夫大会，特此致信了解更多有关票价的信息。
