即使在战争结束后，他们仍继续通信了数十年。

Even after the war ended, they continued to ___correspond for decades.

我们作为笔友通信多年，但从未见过面。

We've been ___corresponding for years as pen pals, but we've never met in person.

在电子邮件出现之前的年代，我的祖父母常与海外的朋友通信。

In the age before email, my grandparents used to ___correspond with friends overseas.