Usages of serio
Nuestro nuevo profesor es muy majo, pero a veces parece serio en clase.
Our new teacher is very nice, but sometimes he seems serious in class.
La jefa de mi hermana es seria, pero en persona resulta bastante maja.
My sister’s boss is serious, but in person she turns out to be quite nice.
Elon.io is an online learning platform
We have an entire course teaching Spanish grammar and vocabulary.