这不就是介词短语做后置定语么？多么简单

【原创】一个语法问题请教一下
想请问一下如下这道题，是初中练习上碰到的，
I found that _____ with those people was very difficult. (communicate)
这道填空题答案上是写的communication，但是communication with的形式好像没怎么见过，另外此处如果用to communicate 或者 communicating 是否准确呢？还希望各位能帮忙解答一下。
谢谢各位了
【答】填 communication 是正确的。communication with sb. 的意思是“与某人沟通”。如：
Parents need to have good communication with their children . [= they need to be able to understand and be understood by their children.] 父母应该与孩子保持良好的沟通。（摘自《韦氏高阶英汉双解词典》p.417）问题中的 that 引导一个宾语从句。