Alternate construction of «cayeron los libros.»
Do these two sentences translate with exactly the same meaning?
«Se te cayeron los libros.» You dropped your books. ???? «Se cayeron los libros suyos.»
1 Answer
"Se te cayeron los libros" is fine when you want to say: you (tú) dropped your books. "Se cayeron tus libros" is what you say if they fell independent of you (tú) dropping them. "Se cayeron sus libros" is related to: los libros de él, los libros de ella, los libros de usted, los libros de ustedes o los libros de ellos.
Hence, "se cayeron los libros suyos" is incorrect. The two sentences above translate quite differently.