Sue walking with difficulty.

Sue is walking with difficulty.不良于行
I saw Sue walking with difficulty.

doing something with difficulty, 做某事有困难/不方便
可以把它当成词组用，但只是介词with 和difficulty的组合。也可以改用其它的字，像ease,happy mood,等。

He always solves math problems with ease.
他总是轻而易举地解数学题。

词组
with difficulty
困难地

吃力地

例句
He has difficulty with humanrelations.
他的人际关系不好。

with difficulty
困难地
吃力地

carry with difficulty 吃力地搬运

是固定词组，做方式状语，”困难地”

He told me with difficulty that he had been ill for quite a few months.句意为：”他艰难地告诉我已经病了好几个月了．”