have difficulties with和have difficulty with

题目

have difficulties with和have difficulty with
2者是相同的吗?
为什么i have some difficulty (in) solving this problem这里不用复数?
some翻译为某一吗?

答案

have difficulty/trouble (in) doing sth.在这里difficulty和trouble都不可数.some可以修饰不可数名词.
一般没有have difficulties doing sth.这样的用法.