HELP please... silly translation problem

[alayi]

Okay, so, for Thanksgiving, we're supposed to write a list of things we're grateful for. The form which my teacher (through a substitute teacher) gave us was,

"Gratis ago" + dative

But she wants us to use a participle in each sentence. (?!) The example she gave us was,

"I am grateful for having friends."

I am confused about multiple things.

A, I don't understand why this is a participle and not a gerund, as it seems to me that it should be a noun, and a participle functions as an adjective or a verbal, agreed? And if it's a present participle that's substantive, it would mean "he/she/it/they etc. who are ____ing." Right?
B, I don't understand where "gratis ago" comes from. Doing a little dictionary research, I found that the verb agere when used together with gratias means to express thanks. The verb habere, however, would mean to have thanks, which is the intended meaning. Now, I don't understand where "gratis" comes from. Apparently it's a shortened form of gratiis, which is of course the ablative or dative plural form of gratia. Or, it could be the ablative or dative plural of the adjective gratus, grateful. I'm not really sure how either fits into the sentence.

Could someone please explain? Thank you!

[benissimus]

Okay, so, for Thanksgiving, we're supposed to write a list of things we're grateful for. The form which my teacher (through a substitute teacher) gave us was,

"Gratis ago" + dative

But she wants us to use a participle in each sentence. (?!) The example she gave us was,

"I am grateful for having friends."

I am confused about multiple things.

A, I don't understand why this is a participle and not a gerund, as it seems to me that it should be a noun, and a participle functions as an adjective or a verbal, agreed? And if it's a present participle that's substantive, it would mean "he/she/it/they etc. who are ____ing." Right?

You are correct, it should be a gerund and not a participle, which are the same in English but distinct in Latin.

B, I don't understand where "gratis ago" comes from. Doing a little dictionary research, I found that the verb agere when used together with gratias means to express thanks. The verb habere, however, would mean to have thanks, which is the intended meaning. Now, I don't understand where "gratis" comes from. Apparently it's a shortened form of gratiis, which is of course the ablative or dative plural form of gratia. Or, it could be the ablative or dative plural of the adjective gratus, grateful. I'm not really sure how either fits into the sentence.

She must mean gratias ago, but you are right that it doesn't really make sense. This phrase is for thanking someone, not for being thankful. Don't dismiss the possibility that you may be a little brighter than your teacher A more practical phrase for this situation might be (abl. gerund) + gratus/grata sum "I am grateful on account of ____".

[alayi]

I think I might just "forget" to copy down her "instructions."

Thank you so much!

*figures she'll get an A on it no matter what she has on her paper, so she might as well be right*

[alayi]

I gather that gerunds don't usually have direct objects, but is it okay here? I read that where a gerund would have a direct object, the gerundive is normally used instead, but that's future tense... doesn't make sense in my sentences and neither does a perfect passive participle.

[benissimus]

Gerundive should not be thought of as future for all intents in purposes, though some textbooks confusingly mark it as so. In all but a very few exceptional cases it merely shows obligation or replaces the gerund when a direct object is needed.

[alayi]

My textbook wasn't really clear on that. Thanks...