Since "ser" is more of a "permanent thing" or "Identity" we can conclude that estar is used as a "condition" or "temporary thing"
For example: Yo soy (ser conjugated) Jay ( I am Jay) - My name is an identity and is permanent
Yo estoy (estar conjugated) bien (I am good/well) - I am feeling an emotion and an emotion can be considered a condition or temporary.
Ellos comenzan las clases a las nueve.
Translated to they started classes at nine.
so comenzan is the right one
Answer:
have a good day
Explanation:
6:15pm : Las seis y cuarto de la manana.
1:30pm : La una y media de la tarde.
9:50pm: Las nueve y cincuenta de la noche.
Los caracoles crecen y dejan su caparazón para buscar uno nuevo
