difficulty后接in doing sth时，意思是“做某事有困难”，其中的介词in含有while的意思，表示“当……的时候”“在……的过程中”，整个结构的意思是“当做某事的时候有困难”“在做某事的过程中有困难”。如：
We had difficulty in finding a parking place. 我们费了很大劲才找到一个停车位。
They shouldn’t have any difficulty in finding the house. 他们找这房子时大概不会有困难。
If you should have any difficulty in getting spare parts ring this number. 万一你买备件时遇到什么困难，请打这个电话号码。
One way of deciding what to do when you have difficulty in choosing the best course of action is to toss a coin. 当人们遇到困难不知选什么行动方案最好的时候，一个办法就是扔硬币来决定干什么好。
注：该结构中的介词in有时可以省略。如：
I had difficulty carrying out the plan. 我执行这项计划有困难。
She was having great difficulty getting her car out, and so I had to move my car to let her out. 当时她正无法把车子开出来，所以我就移开了我的车子让她开出来。
另外，若difficulty后没有出现动名词，而是接名词，则要用with sth。如：
Some people had difficulty with the lecture, but most understood. 有些人听讲有困难，但大部分人听懂了。
If you have the least difficulty with the arrangements for the conference, phone me at once. 如果你安排会议有什么困难，马上给我打电话 初三。
二、后接about doing sth
difficulty后接 about doing sth时，表示关于做某事的困难，其中的介词about意为“关于”。如：
There shouldn’t be any difficulty about getting you a visa. 给你弄个签证不会有什么困难吧。
注：about后也可直接跟名词作宾语，此时的about仍表示“关于”的意思。如：
There oughtn’t to have been any difficulty about it 此事本不应有什么困难。
此时还可用介词over表示类似意思。如：
There doesn’t seem to have been any difficulty over the money question. 在钱的问题上似乎没发生什么困难。
三、后接of doing sth
difficulty后接of doing sth时，表示做某事的困难，其中介词of表示所属关系，相当汉语的“的”字。如：
He tried to explain to me the difficulty of learning to cook from books. 他向我解释照着书本烹饪的困难。
One of the annoyances of working here is the difficulty of parking near the office. 在这里有一件伤脑筋的事，就是在办公处附近很难停车。
Both “feat” and “achievement” emphasize the difficulty of accomplishing something mental or physical. feat和achievement均着重指在脑力或体力方面完成某事物的艰巨性。
注：of后也可直接跟名词作宾语，此时的介词of仍表示所属关系，意为“……的困难”。如：
She has no notion of the difficulty of this problem. 她不了解这个问题的难处。
Do you understand the difficulty of my position? 你了解我处境的困难吗?
本文来自：逍遥右脑记忆 https://www.jiyifa.com/chuzhong/36166.html
相关阅读：above 与 over的用法区别