Letters survivethat afford us a glimpse into his everyday life.
survive可将来接that-从句吗？但我在词典中没查到如此的使用方法啊！
你的理解有误。这里的 that-从句不是宾语从句，它是定语从句，是修饰名词 letters 的定语从句，只不过因为句子谓语部分过于简单，只有一个动词 survive，所以才将这个定语从句后移了，以维持句子结构平衡（防止所谓的头重脚轻）。即：
Letters survivethat afford us a glimpse into his everyday life.
=Letters thatafford us a glimpse into his everyday life survive.
让大家大概一窥他平时生活的信件保存了下来。
类似的结构如：
Many came whowere not invited. 很多没被邀请的人也来了。
Word came that Iwas wanted at the office. 有人带话来，说办公室那里找我去。
News came thatthe murderer had given himself up. 有消息说，杀人犯已经投案自首了。
