i found that ——— with those people was quite difficult.(communicate)communication 为什么不用 communicating?

i found that ——— with those people was quite difficult.(communicate)communication 为什么不用 communicating?
i found that ——— with those people was quite difficult.(communicate)
communication 为什么不用 communicating?

i found that ——— with those people was quite difficult.(communicate)communication 为什么不用 communicating?
以上结构是：I found that+名词性从句
而从句中的with those people 是介词短语（你可以把它放在句后或是所修饰的词的后方都可以,或者直接删去也行,反正不影响从句的完整性）如：
i found that communicationg was quite difficult!
介词短语作定语修饰名词或代词时,必须后置.而这里的介词短语作定语修饰的则是主语.
从句中还缺主语,而主语则应该是名词或具有名词性质的词,communicatede 名词是communication而不是communicating.
根据你提出的communicating,你可能误认为动词凡是加上ing就变成了动名词,实质上不全是一样的!加上ing成了动名词具有名词性质的有fighting、washing……
动名词作主语、宾语和表语
如：
1）作主语
Fighting broke out between the South and the North.
南方与北方开战了.
2）作宾语
a.动词后加动名词doing作宾语 V.+ doing sth
admit 承认 appreciate 感激,赞赏 avoid 避免
complete 完成 consider 认为 delay 耽误 deny 否认 detest 讨厌 endure 忍受 enjoy 喜欢 escape 逃脱 prevent阻止
fancy 想象 finish 完成 imagine 想象 mind 介意 miss 想念 postpone 推迟 practise 训练 recall 回忆 resent 讨厌 resist 抵抗 resume 继续 risk 冒险
suggest 建议 face 面对 include 包括 stand 忍受 understand 理解 forgive 宽恕 keep 继续
举例：
(1) Would you mind turning down your radio a little,please?
(2) The squirrel was lucky that it just missed being caught.
b.词组后接doing
admit to prefer…to be used to lead to devote oneself to object to stick to be busy look forward to to为介词）
no good,no use,It's worth…,as well as,
can't help,It's no use /good be tired of
be fond of be capable of be afraid of
be proud of think of / about hold off
put off keep on insist on count on / upon
set about be successful in good at take up
give up burst out prevent … from…
3）作表语
Her job is washing,cleaning and taking care of the children.
常见介词短语的有表示所属的of短语,表示伴随状态的with短语,表示方位或穿戴的in短语等.例如：
The girl in the red hat is my younger sister．戴红帽子的女孩是我妹妹.
China is a great country with a long history．中国是一个历史悠久的伟大的国家.
She is only a girl of ten years old．她只不过是个十岁的小女孩.
The picture on the right is more beautiful．右边的画更漂亮