A personal letter will usually brighten up a person's day.

一封私人来信往往就能使人一天心情愉快。

《牛津词典》

A man who knows how to write a personal letter has a very powerful tool.

一个知道如何写私人信件的人有一个非常强大的工具。

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Despite the growing importance of computers, however, there will always be a place and need for the personal letter.

尽管计算机的重要性日益增加，但私人信件总有其一席之地，对其需求亦仍然存在。

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The pope made a highly unusual personal analysis of the case in a letter to Roman Catholic bishops around the globe that was made public Thursday by the Vatican.

VOA: standard.2009.03.12

U.S. President Barack Obama apologized to Afghan President Hamid Karzai in a personal letter.

WSJ: U.S. Pulls Out Advisers After Two Killed in Kabul

In the 1980s and '90s, email saved the personal letter from extinction by moving it online.

WSJ: David Gelernter: The Pros and Cons of Cyber-English

If you really want to move people, send them a personal letter or card, in your own hand writing.

FORBES: Young People, Stop Just Texting Me and Give Me a Call Once in a While PLZ! Part Deux