Remembering is the gerund of the verb - to remember.
An adjective describes a noun - The QUICK boy - Quick is the adjective describing the noun boy.

An adverb describes a verb - The boy runs QUICKLY - Quickly is the adverb decribing the verb to run.

Eddy is spot on. Think of a gerund as a noun in verb's clothing.

"What do you like'"]
"Running, skiiing, cooking, and relaxing."

These are all gerunds. In your sentence, there is an implied "with": Mary has trouble with remembering...

In Spanish, this function of the gerund is performed by the infinitive. So the translation of your sentence might be:

"Mary tiene dificultades en/para recordar su tarea."

Another example:

Remembering dates is difficult for me.
El recordar las fechas es difícil para mí.

I am becoming Gerund, whom is destroying verbs!

(Sorry, had to say it)

The gerund is not destroying the verb. I think it is a form of the verb functioning as a noun. You just need to learn these grammatical points. Believe me, I find it difficult but I just persevere.

Rob, remember that there are 16(') different verb conjugations in spanish and the gerund is only one of them I think. My spanish teacher keeps telling me, but I keep forgetting how many.

Eddy,

I am needing to be giving an apology. I was reading a newsgroup long ago, and reading that sentence had been making me become laughing. It may be more applying to english and meaning less to Spanish!

(English Learners: Don't use the English gerund like that!)