Breakdown of Avistamos más patos de los que esperábamos.
de
from / of
los
the (masculine plural)
esperar
to wait / to hope / to expect
que
that / than
Questions & Answers about Avistamos más patos de los que esperábamos.
Why do we use de los que here instead of just que for the word "than"?
When comparing a noun (patos) with an action or conjugated verb (esperábamos), Spanish uses de + a definite article + que to mean "than". Since patos is masculine and plural, we use los, giving us de los que. You would only use que if you were comparing two nouns directly, like más patos que gansos (more ducks than geese).
Could we use the neutral de lo que here instead?
No, because you are specifically comparing a concrete noun (patos). The comparison phrase must agree in gender and number with that noun. You would only use the neutral de lo que when comparing a general idea, an adjective, or an action rather than a specific noun.
Why is avistamos in the preterite but esperábamos in the imperfect?
Is the verb avistar related to the word vista?