No sé dónde guardé la cartera.

I don't know where I put the wallet.

Breakdown of No sé dónde guardé la cartera.

• yo: I
• saber: to know
• no: not
• la cartera: the wallet

Questions & Answers about No sé dónde guardé la cartera.

Why do sé, dónde, and guardé have accent marks?

They each have an accent mark for a different reason:

• sé: the accent distinguishes the verb sé (I know) from the pronoun se.
• dónde: question words like qué, cuándo, dónde, cómo take an accent when they are used in a question, even an indirect one such as No sé dónde...
• guardé: the accent marks the first-person singular preterite ending -é and shows that the stress falls on the last syllable.

So the accents are not random; each one tells you something useful about grammar or stress.

Why is guardé used here instead of guardaba?

Guardé is the preterite, which is used for a completed action in the past.

That fits this sentence because the speaker means: at some point, I put the wallet somewhere, and now I do not remember where.

If you said guardaba, that would sound more like:

• a repeated or habitual action, or
• background description

So guardaba would not fit as naturally here.

Compare:

• No sé dónde guardé la cartera. → I put it somewhere once, and I do not remember where.
• Guardaba la cartera en ese cajón. → I used to keep the wallet in that drawer.