French language Q&A Forum

This lessons specifically states that: 

To conjugate apparaître in Le Passé Composé (Indicatif), both auxiliaries avoir and être are perfectly valid and interchangeable while the meaning remains the same.  In terms of usage, être is used more often than avoir in colloquial speech.  

I've seen the comments below about one is used more for appearing, but why is mine wrong?

Soudain, j'ai apperu derrière eux

Why is it the Canal du Midi and not the Canal de Midi, given that Midi describes the Canal and not the Midi is possessive of the Canal.   

Is there any difference in the meaning or tone of “comment ça se fait” compared to “pourquoi”? In English, we sometimes say “how come” rather than “why” to avoid sounding curt or accusatory. Thank you!

One suggestion given for the translation of 'we'll drink it without rushing' is 'nous le boirons sans se presser'. Would it be wrong to say 'nous le boirons sans nous presser' instead?

The lessons says to use either. Where is the explanation/lesson details? 

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?

Does anyone have any recommendations of how to get a full on immersive french experience in France? I am trying to get ready for DALF C1 exam and want to improve fluency quickly. I am looking for 2–3 weeks in France ideally with 3-4hours of structured learning. Ideally staying with someone who speaks only french. Institute Francais seems to have something but it is very expensive and probably too intense. 

"Depuis que Catherine a changé de carrière il y a quatre ans, plus personne ne la reconnaît."  I understand this to mean "Ever since Catherine changed her career four years ago, no one recognizes her anymore."  I would never have known where to put that "plus!"  I might have thought "personne ne la reconnait plus."  Would that have been wrong if I had been constructing the sentence instead of doing it as a dictation?

And a couple of little periods have been inserted in the vocabulary section at the beginning: eg. te.lle.  I like to look at this section as the whole piece is being read to me and I noticed these tiny typos.

Hi, in the line “nous avons développé des intérêts communs” I believe I’m hearing a short connecting word/syllable between “intérêts” and “communs”. Am I imagining this?

Surely it is le mien? Please explain