French language Q&A Forum

When expressing the idea of passing by or popping into someone’s place is par always needed as well as chez? Examples in this lesson and the other on different uses of passer differ. 

Elle est passée chez Laurent hier. She passed by Laurent’s place yesterday.

Yann passera par chez Laura après le travail. Yann will pass by Laura’s place after work.

As in, I know that 'un' in masculine, and 'une' is feminine, but how do you tell if an everyday object is masculine or feminine.

;

Should this not be :

Ce fil est apparent, mais apparemment personne ne l'a pas remarqué.

To add a pas?

Pense-t-on que Caligula était fou?

For I haven't stopped all day..., shouldn't one say, "Je n'ai pas m'arrêté une minute...  (i.e., i haven't stopped myself). Isn't arrêter alone mean arrêter + qqch ? Or in the case it is implying "Je n'ai pas m'arrête (+faire qqch) so the reflexive is not used. 

Also in French is there a way to distinguish: 1) We are all keeping our fingers crossed, and 2) We are keeping all our fingers crossed? (or in general: We are all selling our qqch vs. We are selling all of our qqch where qqch is a masculine noun? ).