Learn Spanish (Latin America): Estos papeles los amontonaste y nunca los descartaste. - These papers, you piled them up and never discarded them.

This is a structure called topicalization. When you move a direct object like Estos papeles to the front of the sentence to emphasize it, Spanish requires you to double it by adding the matching pronoun los right before the verb.

Why do we have to repeat "los" before "descartaste"?

In English, it is common to say "You piled them up and never discarded," dropping the second pronoun. Spanish is more explicit. Because you have two distinct conjugated verbs (amontonaste and descartaste), you must use the pronoun los before each one to show what is receiving the action.

What is the difference between "amontonar" and "apilar" for piling things up?

Both mean to pile or stack, but amontonar (from un montón, meaning a heap or pile) often implies a messy, disorganized heap. This makes it a great choice for old papers. Apilar implies a neater, more orderly stack.

Could I use "tiraste" or "botaste" instead of "descartaste"?

Absolutely. Descartar means to discard or rule out, which works well for sorting papers. However, everyday alternatives like tiraste or botaste (the latter being very common in Latin America) are perfectly natural if you just mean throwing them in the trash.