(relative)which(pronoun referring to a preceding clause)
Llegó tarde, lo que me molestó. ― He arrived late, which annoyed me.
(in comparative constructions, after de) Introduces a subordinate clause expressing the standard of comparison following a main-clause comparative word or phrase (más, menos, mejor, peor, antes, etc.); than [what, how]
Esperaba que me entretuviera esta película más de lo que hizo.
I was hoping this movie would entertain me more than it did.
Se lo prometo a todos que la situación parece mucho peor de lo que es en realidad.
I promise you all that things appear much worse than they actually are
