habrán parecido
-they/you will have seemed
Future perfectellos/ellas/ustedesconjugation ofparecer.

parecer

Todos ellos son logros notables, que al principio del proceso de la Convención a muchos les habrán parecido imposibles.
These are all remarkable achievements, which many would have believed impossible at the outset of the Convention process.
Word of the Day
to boo