The answer is (acabe) because it refers to the fact that he has not finished his studies and when he finishes it he could finally be an astronaut.
Hey there!
You use "ser" in Spanish when describing the following.
Descriptions
Origin or Nationality
Characteristics
Time
Occupation
Relationships
I will give an example of each of these.
For description, you could say your name, or a physical attribute.
For ser, you use "soy" for "am".
Yo soy Enrique
"I am Enrique"
Yo soy bajo.
"I am short"
For origin, you can talk about a place you are from.
Soy de La Republica Dominicana.
"I am from the Dominican Republic."
For characteristics, you could use an adjective to describe yourself or say something like...
Soy una persona buena.
"I am a good eres."
Or....
Tu eres malo
"You are bad"
For time, you usually just use it all to refer to times such as times of day or days, months, years, etc.
Hoy es jueves
"Today is Thursday"
Ayer fue miercoles
"Yesterday was Wednesday"
For occupations, you just talk about jobs and careers.
Tu eres una pintura
"You are a painter"
Soy una doctora
"I am a doctor"
For relationships, you refer to one's relationship to you.
Tu eres mi mama
"You are my mom"
Yo soy el amigo de Juan
"I am Juan's friend"
or
"I am a friend of Juan"
I hope this examples help you out! I'm taking Spanish 1 too. :)
