Past Participle and Preterites.

Question

When would I ever choose to use the Past Participle form of a word (-ido, -ado) over the Preterite (-é, -aste, -ó) (-í, -iste, -ió)?

the past participle is the equivalent to adding -ed to a word in english (Jump -> Jumped) However, the Preterite conjugation of a verb automatically implies that it happened in the past. (Ver -> Vi)

Hopefully, you understand my confusion.

Answer 1

Kiwi's right.

Participles are used just like they are in English. Participles connect something into the past with the present. (perfect tense)

I have never seen him. = Nunca lo he visto.

[connected to the present...it has never happend, starts in the past and continues to now]

I saw him = Lo vi.

[you saw him and it's done.]

Kiwi gave a good example with he comido

"Did you eat?" would just be asking the question, the asker wants to know a fact if you ate today. "Have you eaten" would imply that the asker wants more information, as in "are you still hungry....Do you want me to make you something..."

-Relating a fact w/ preterit-

"¿Comiste tú? Did you eat?

-"Si, comí una ensalada." OR "No, no comí nada." Yes, I had a salad/ No I didn't eat.

-The asker is wanting more information, the question goes farther than fact w/ prfct.-

"¿Has comido ya?" Have you eaten yet?

-"No, todavía no he comido." No, I haven't eaten yet

"¿Quieres que prepare algo para ti?" Do you want me to make something for you?

The first example could still be used in the same manner as the second...but it's more common for the second example to be used when expressing connectivity to the present, or a desire for more information besides relating a fact.

"¿Comiste ya?" Did you eat yet?

-"Todavía no, pero tengo hambre." Not yet, but I'm hungry

"Claro, ¿quieres que prepare algo para ti?" Okay, do you want me to make something?

Answer 2

As you say the preterite is a tense in itself and refer to a past action - eg. comí - I ate. Completed in the past and little to do with the present.

The past participles however must be used to make perfect tense such as the past perfect. He comido. I have eaten.

Just like the English there is a difference with the perfect tense having some connection to the present.

Taking the he comido example you might say that in response to the question, 'would you like something to eat' (now, in the present') - making a connection between the past and the present.

I hope that helps somewhat