Neutral article
See also: Artículo and Article types
In Spanish there is a neutral article, lo, that can be used in different ways.
Before an adjective
Lo bueno de Marta es su generosidad.
The good thing about Marta is her generosity.
Eso es lo peor que me ha pasado en mi vida.
That is the worst thing I have [ever] experienced in my life.
Before an adverb
¡Lo bien que lo pasamos ayer!
What a great time we had yesterday!
No puedo creer lo lento que conduces.
I can't believe how slowly you drive.
Before a prepositional phrase
Lo de Luis no te lo puedo contar porque es un secreto.
I can't tell you that thing about Luis because it is a secret.
No quiero que se vuelva a repetir lo de esta mañana.
I don't want what happened this morning to ever happen again.
Before que
Lo que me dijo mi madre me sorprendió.
What my mum told me surprised me.
No tengo ni idea de lo que me estás contando.
I have no clue what you are talking about.
As a superlative
Sois de lo peor.
You are the worst.
Esta película es de lo más interesante.
This film is incredibly interesting.