Elles (les chauve-souris) ne volent que la nuit

Question

I look for a proposition like à or dans la nuit.  Have you any general tips on why and where french does not need a preposition in cases like this?

Aurélie Drouard · Accepted Answer

Bonjour Jennifer !

With moments of the day, you will usually use only the definite article "l'/le/la" to express a general statement:
"Le soir, je me couche tard." (In the evening, I go to bed late.)
"L'après-midi, il fait la sieste." (In the afternoon, he has a nap.)
"La nuit, nous dormons." (At night, we sleep.)

See also our lesson on days of the week:
Using "le" with days of the week + the weekend (French Definite Articles)

I hope that's helpful!
À bientôt !

Jennifer Cole · Answer

Merci Aurélie,

Prepositions one of my bêtes noires.  I read your lessons but difficult to keep them in mind.  Thank you again.

Aurélie Drouard · Answer

Courage Jennifer !

"C'est en forgeant que l'on devient forgeron !" 
(Literally: It's by forging that you become a blacksmith.)
-> Practice makes perfect. 
:)