preterite and variations in meaning
One of the other websites I am using to learn Spanish says that in the preterite, verbs can have different meanings from the imperfect:
María quiso comprar la casa. Maria tried to buy the house. (completed action) Juan quería comprar la casa. Juan wanted to buy the house. (no definite beginning or end)
This is one example using the verb 'querer'.
I tried putting
'María quiso comprar la casa.'
through a translater, but it comes back as
'María wanted to buy the house.'
I'm a little confused, because 'tried' and 'wanted' are totally different and if verbs can have different meanings in different tenses, does that mean there are different dictionaries for the different tenses, or should I just forget this completely.
No, you can't just forget it because it's important! The translator just isn't able to distinguish between subtle meanings in Spanish.
You are right that "quise" means that she tried to buy the house, and Juan "quería" wanted to buy the house.
Also important to note: "no quise" means refused and "no quería" means he didn't want to.
Another one I just remembered is the verb "saber." In the preterit it means "found out." For example, "Supe la verdad. (I found out the truth). However, in the imperfect it means that I knew something. For example, "Sabía la verdad." (I knew the truth).