选A.difficulty 的惯用法有这么几种：difficulty in doing sth.如例句.difficulty of sth.如：You don't know the difficulty of the problem.sb.has difficulty with sth.如：I have a lot of difficulty with ques...sb. has difficulty with sth是什么意思遇到麻烦的意思，比如：I have difficulty with this question. 直译：我在这个问题上遇到了困难/麻烦。意译：这个问题对我来讲比较难/有难度。
也可用于人：I have difficulty with him. (与他很难相处/无法相处/难了解他)。

还有问题吗?