"Pudo" vs. "Podía", "Tuvo" vs. "Tenía", "Quiso" vs. "Quería"
I can never decide whether to use the preterite of imperfect when dealing with tener and poder in the past. A couple examples:
I couldn't come to class on Monday because I had to accompany my mother to the doctor. No podía/pude venir a clase el lunes porque tenía/tuve que llevarle a mi madre a la oficina del médico.
He wanted to borrow money from me, but I did not have money to lend him so I refused. Quería/Quiso pedirme prestado dinero a mí, pero yo no tuve/tenía dinero para darle y por eso negué
We couldn't go because of the bad weather. No podíamos/pudimos ir porque hacía mal tiempo.
¡Gracias!
5 Answers
I get why you are having trouble with this... In your first example, both can be right, but make sure to use either podía with tenía or pude with tuve, in this case the tenses have to match. The literal translation would be "No pude...", bacause you used couldn't.
In your next example, both quería and quiso would be fine, but you should use tenía and not tuve, bacause you are talking about your situation at that moment. (So matching it with quería might be better. By the way, if you already said "pedirme" you don't have to add "a mí" "me" at the end of the word is already referring to you. However, you do need to add a "me" before negué ("me negué")
A mí can be used, for example, when you answer a question:
¿A quién le tengo que entregar el dinero?
A mí.-
In your last example, you can also use either podíamos or pudimos.
Hope this helps.
¡Saludos Michoacanos!
Hello Miller 
When reading your post I remembered something that I had read in my book: ''Barron's 501 Spanish verbs'' (7th edition) by Christopher and Theodore Kendris, about some important and relevant points about the use of the preterite.
In the introductory pages of this book, it explains how and when to correctly use the different verb tenses and moods.
Under tense number 3 Preterite (which expresses an action that was completed in the past) they say:
In Spanish some verbs that express a mental state have a different meaning when used in the preterite.
They then go on to list and give examples of 5 verbs that do this but give 7 examples including positive and negative constructions. I will list all the verbs conocer, poder querer, saber and tener ...and then give examples relevant to your question: poder querer and tener.
1 Pude hacerlo = I succeeded in doing it (Poder which means to be able means succeeded in the preterite)
No pude hacerlo = I failed to do it. ( Poder when used in the negative in the preterite, means failed or did not succeed)
2 Quise llamarle = I tried to call you. (Querer which means to wish, want or to love, means tried in the preterite)
No quise hacerlo = I refused to do it.
3 Tuve una carta de mi amigo Roberto.= I received a letter from my friend Robert.
(Tener which means to have, means received in the preterite)
I hope these examples help you understand how the meaning of a verb changes when written in the preterite as opposed to the imperfect
You see, the thing is you are not refusing him, it's like you're refusing yourself to give him the money. ("Negar" is a transitive verb, so you need to negar something) You can say "le negué el dinero" (something likeI denied the money to him), but this means something different. "me negué" means you are not denying the money, but yourself from giving it to him (because you don't have it, of course)... Hope it's clear, if not, ask me and I'll try to explain it better :D
Good question, man. I know that this question isn't relevant to the question asked..but I was wondering, when using indirect obejcts(such as in the example above when you said "llevarle a mi madre"..could you have just said "a mi madre" and not attached the "le" to the end of the infinitive?
I understand that this is probably just for clarification's sake.
I have another question:
In this sentence "Quiso pedirme prestado dinero a mí"...can someone please explain why "pedirme" is used here followed by "prestado"? I don't understand.
