French language Q&A Forum

I did a simple quiz.  One of the problems was to translate "We have a cat"  - I used the  nous avons... option.  It was wrong stating "On a..." is the correct answer.  How can one tell if an informal response, or the commonly spoken one is the correct choice out of context?  It sees to me, both answers are equally correct.  What am I missing?

Merci

I know that se sentir and aller identical. But in this exercise it does not work.

Franck________ en pleine forme.

       Answer: se sent

Franck va en pleine forme. It is false. I wonder why it is incorrect?

My question is about a quiz question in this unit: "J'ai décidé d'apprendre à jouer du piano cette année." How do you know it's "apprendre *à* jouer" instead of "apprendre *de* jouer," for example. I think that French verbs differ in this respect, but I haven't seen any systematic explanation of it, and I don't even know how to talk about it in a way that could make internet search productive. Do you have any teaching materials about this, or can you help me to understand it better? Thanks in advance.

Thank you