"Nous nous écrivions des lettres d'amour en secret."

Translation: We used to write each other love letters in secret.

[LSadun]

Stop insisting that we use "used to" to translate every sentence that is in the imperfect! That isn't how English works.

[Jane695536]

"we used to write each other love letters secretly" is marked wrong, why?

[B.Ellis]

We were writing each other love letters in secret Marked wrong (But this is how people actually talk )

[XgwJ4UVx]

Exactly - any decent editor would delete the "used to"; it is just extraneous verbiage. An English speaker or writer would say "wrote." Does Duo have any native English speakers?

[KenAndresen]

"We wrote some love letters to each other in secret." marked wrong and reported.