1. Have difficulty (in) doing something
最常用结构，后接动名词（-ing形式），介词 in 可省略。
例句：She has difficulty (in) understanding the accent.
2. Struggle with doing something
强调「费力应对」，语气较强，with 后接名词或动名词。
例句：He struggles with solving complex math problems.
3. Find it hard to do something
直白表达，后接不定式（to do），适用于口语和书面语。
例句：They find it hard to adapt to the new environment.
其他替换表达（备选）：
Have a hard time doing something（更口语化）
I had a hard time finishing the project.
It's challenging to do something（强调挑战性）
It's challenging to master a new language.
根据语境和语气选择合适表达即可 ✅
