我的祖父母相识后，几十年来一直定期通信。

My grandparents ___corresponded regularly for decades after they met.

我们通信多年，所以最终能亲自见面真是太好了。

We've been ___corresponding for years, so it was great to finally meet in person.

在调研期间，这位学者与全国各地的专家通信以收集数据。

While researching, the scholar ___corresponded with experts across the country to gather data.