French language Q&A Forum

Why is "l'une" incorrect here? Maybe this logic is incorrect but I guessed that because you already have ce (c'est) in the sentence it would be repetitive to have another pronoun right after. I saw another question about it but am still confused in which contexts it is OK to use "l'un" and when to use "celle" and its other varieties 

In this text the question used “te plait…” and the answer was “j’aime…” Why? What is the general rule? Thanks!

1) Introduction uses "de la laine" for wool, but when used the answer uses "de laine." The intro is not consistent with the lesson.

2) hint "chapeau" = winter hat, answer uses bonnet and marks chapeau wrong.

Why in the sentence "Claire habite à Paris." is the mute h clearly pronounced?

Becherelle (2006) says to conjugate gémir as you would finir, interestingly, nothing looks like geignait there ... I assume I haven't got to the lesson that explains this. 

Why does the text switch from using 'nous' and 'on'  as in 'ce qui nous ferait une nuit de plus à la belle étoile/on fera les courses'

In the alternative translations, where nous is used, on was not an option. How do you know when to use nous and when to use on?

"j'ai acheté un sac à dos qui est très à la mode en ce moment, et j'ai pris un nouveau stylo-plume et beaucoup de cartouches d'encre." 

Why isn't neuf used here? Nobody, generally, buys a used object when going back to school.