What is the difference between Just and Only?
Just and only can mean the same thing, but they do have differnt meanings too.
Meaning 1 (they mean the same thing) I just have one sister = I only have one sister
Meaning 2 (when we are talking about an action that has been performed very recently) I = just got here, I just ate, i just had a baby.
Here is a good explanation
http://www.espressoenglish.net/difference-between-just-and-only/
just is I just arrived acabo de llegar in that momento en este momento como acabar de just finished the work acabo de terminar el trabajo. I just spoke to my father. acabo de hablar con mi padre.
I only want to do this job. I only want to study and nothing else. nada más
me quiero solo trabajar en este trabajo. only como se hace este trabajo este estudio y no más que la otra.