When to use each one

1. When to use “a ser” 

This phrase means “to be” or “to become.” The verb we are using is the verb SER

• Ella va a ser médico
• El va a ser muy famoso
• Nosotros queremos aprender a ser más independientes
• Usted va a ser mi mejor amigo

2. When to use “a hacer” 

“Hacer” means “to do/make,” The verb we are using is HACER. 

When “hacer” is combined with verbs that require the preposition “a” then we need to say “a hacer” otherwise we just say “hacer”

Verbs that need the preposition “a”

The preposition “a” has to go after the verbs “Ir” “comenzar”, “aprender”, and “volver” when the next word is a verb too. 

• Let’s start to do our homework – Comencemos a hacer la tarea
• We are going to exercise- Vamos a hacer ejercicio
• I learned to make muffins – Aprendí a hacer pastelitos
• I will do my homework again – Volveré a hacer mi tarea

Verbs that don’t need the preposition “a”

For all other cases, we just use “hacer” with out the “a”

• I want to make muffins- Quiero hacer pastelitos
• I like to make noise- Me gusta hacer ruido
• She needs to do her homework – Necesita hacer su tarea