Amane's mother, Shihoko, arrives at the apartment without warning while Mahiru is visiting. Amane asks Mahiru to hide, but Shihoko eventually finds her, and the two neighbors frantically try to correct Shihoko's assumption that they are dating. Nonetheless, Mahiru is touched by Shihoko's motherly kindness. After Amane sees how happy Mahiru is to be called by her first name, he tries calling her "Mahiru" too. From that day on, the neighbors call each other by their first names.
You have to call your girlfriend 
by her first name, you know.
عليك أن تنادي حبيبتك باسمها الأوّل
Sabes que tienes que llamar
a tu novia por su nombre, ¿no?
Sabes que tienes que llamar
a tu novia por su nombre, ¿no?
Tu dois appeler ta copine
par son prénom.
Non sai che tra fidanzati 
bisogna sempre chiamarsi per nome?
Você tem que chamar sua namorada
pelo primeiro nome.
Как ты можешь не называть
 свою девушку по имени?