French language Q&A Forum

It's a pity that once we submit our responses to kwizes that are sent to us by email, we don't get to know where we made mistakes. Perhaps may I suggest that the incorrect answer be indicated in bold red colour or underlined to identity it?

For example,

My score for the Saint Patrick's Day kwiz was 13 correct and 1 incorrect. I did it twice but I think I got the same error? Can you tell me where my mistake was?

My answers are below:

Ma grand-mère est irlandaise, donc dans ma famille on célèbre la Saint-Patrick. Le 17 mars, on accroche le drapeau vert-blanc-orange à la porte, et on colle des petits trèfles irlandaises sur les fenêtres.
Après avoir mangé le ragoût traditionnel de ma grand-mère, ma sœur et moi rejoignons nos amis pour faire la tournée des bars. Je mets mon chapeau haut-de-forme et mon tee shirt préféré avec un farfadet à cheval sur un arc-en-ciel, et ma sœur porte une magnifique fausse barbe rousse et a même un petit sac à main en forme de marmite d'or!
Toute la nuit, on boit de la bière verte en dansant des gigues endiablées !
Joyeuse Saint-Patrick à toutes et à tous !

rejoindre is an infinitive.  Shouldn't it be rejoignons or rejoindrons?

Why not 'chez la tante' rather than 'à la tante'? I thought for a person it should be chez?

I assume that the avoir aspect of the sentence also changes with tense for example: 

Imparfaite =J'avais besoin de= I have needed 

Future= J'aurai besoin de= I will need 

Passe compose= J'ai eu besoin de= I needed 

Plus-que-Parfaite= J'avais eu besoin de= I have had needed

etc. 

Is this correct? 

I don't understand when to use these two "en" and "le/la". For example:

La liberté d'expression est un droit fondamental mais il faut ________ respecter les limites.

I know that "en" refers to La liberté d'expression, but why can't we use "la"?

I know it is only correct to say Je vain manger à huit heures. However, in response to À quelle heure ?,  I've seen the phrase At nine o'clock written as both À neuf heures and A neuf heures. Are both A and À correct to use in this instance?

I wrote cannelle  for cinnamon and was marked wrong  and changed to canelle, but in the dictionary it is spelt cannelle. Which is correct??

The sentence to be translated:

Plus, his songs were extraordinarily varied…..

The correct answer:

De plus, ses chansons étaient si extraordinairement variées….

Why is si required here ? I left it out and was marked wrong.