主语 + have/has/had + (修饰语) + difficulty + (in) + doing sth.
have/has/had：根据主语和时态变化（一般现在时用have/has，一般过去时用had，现在完成时用have/has had等）；
修饰语（可选）：可加great/some/no/little等形容词修饰difficulty，强调困难的程度；
(in)：介词in常可省略（口语和书面语中均常见）；
doing sth.：必须接动名词（不能用不定式），因为in是介词，后面需跟名词性结构。
difficulty的数：此处difficulty是不可数名词（表示“困难”这一抽象概念），不能加s（除非表示“具体的难题”，但该短语中不适用）；
动名词不可替换：不能说“have difficulty to do sth.”，必须用动名词doing；
同义结构：可替换为have trouble doing sth. 或 have problems doing sth.（语气更口语化），或have difficulty with sth.（with后接名词/代词，如“have difficulty with math”=“have difficulty learning math”）。
I have difficulty (in) understanding spoken English.
（我理解英语口语有困难。）
Does she have any difficulty (in) making friends at school?
（她在学校交朋友有困难吗？）
He had great difficulty (in) finishing his thesis last month.
（他上个月完成论文有很大困难。）
We had no difficulty (in) finding your house—your directions were clear.
（我们找你家没困难——你的指引很清楚。）
She has had difficulty (in) getting used to the new job since she joined.
（自从入职以来，她一直难以适应新工作。）
I don’t have difficulty (in) solving this math problem—it’s easy!
（我解这道数学题没困难——很简单！）
Why do you have so much difficulty (in) waking up early?
（你为什么早起这么困难？）
❌ 错误：I have difficulty to learn French.（不能用不定式）
✅ 正确：I have difficulty learning French.
❌ 错误：They have difficulties in working together.（difficulty不可数，不能加s）
✅ 正确：They have difficulty working together.
总结：这个短语是表达“做某事有困难”的标准、正式用法，适用于学习、工作、生活等各类场景，掌握其结构和动名词的使用是关键～