French language Q&A Forum

I know that typically, retourner is used to mean "to go back" and rendre is used to mean "to give back." But on this page: https://www.lawlessfrench.com/grammar/auxiliary-verbs-2/ , which discusses using variable auxiliary verbs in the passé composé, it mentions that retourner can also be used transitively and in that case, it changes its meaning to "to give back." So in the passé composé, can retourner be used in the same way that rendre is?

For example, would both of these be correct?

1. J'ai rendu le livre à la bibliothèque.

2. J'ai retourné le livre à la bibliothèque.

So, when is it appropriate to use "aime" and "aime bien ?"

Hello, I have these 2 lessons coming up at the same time "How to use 'avoir l'habitude de' in French" to express a habit in current or past times and "Expressing past habits or repeated actions with the imperfect tense"  - how do I know which one to use (ie. just the imperfect tense or the expression avoir l'habitude)?   When I go through the test at the end of my 10 lessons I don't know which one is the answer they're looking for.

Why here we cannot use neuf, it is a new bike so it has not been used.Futhermore it is not living things, neuf here sounds make sense.

J’AI FAIT BEAUCOUP D’ERREURS, MÊME SI J’AVAIS ÉTUDIÉ LA PLUPART DES POINTS DE GRAMMAIRE. MERCI BEAUCOUP POUR CETTE LEÇON ET AUSSI POUR L’OPPORTUNITÉ DE POSER DES QUESTIONS. 

In the phrase 'Jules m'apprendra à faire du snowboard', I used 'enseignera' but this was not listed as an optional answer. Could you explain please? Thanks.

Due to my stupidity I missed marking one of my answers but one cannot go back to and answer.  Could this be changed.  Thank you. 

Sylvia

« Elle se maria » [cette année-là] I don’t recognise the conjugation of se marier?

She went to France for vacations, she generally rents a house in the country. Then she goes to the village to buy some fruits and vegetables, and to talk with some neighbors. Then she passes by a beakey and she buys a  warm baguette and a croissant for breakfast. In the afternoon she takes a walk in the country to explore the region. Sometimes she likes to have a fruit tart and she invites a few friends over for a snack. These are very relaxing vacations.

Doesn’t “le dimanche“ mean “on Sundays”? Why isn’t it just “dimanche” to mean on this particular Sunday?