son bonitas

are pretty

→ ser
phrase Rare #36,080
are pretty Used for feminine plural nouns. It can also mean 'are beautiful' or 'are nice' depending on context.
SP: Tus primas son bonitas.
EN: Your cousins are pretty.

Las dos hermanas son bonitas.

Both sisters are beautiful.

Todas las lenguas del mundo son bonitas.

All the languages in the world are beautiful.

Las flores en el florero son bonitas.

The flowers in the vase are beautiful.

No todas las crías de animales son bonitas.

Not all baby animals are cute.

Bien, pero no todas las mujeres son bonitas y sencillas.

Okay, but not all women are pretty and simple.

— Piku (2015)

Ésas son bonitas.

Those are pretty.

Son bonitas.

They are pretty.

— Perfect Blue (1998)