Questions & Answers about Chłopiec miał psa, ale my nie mieliśmy psa.
Why is it miał for the boy but mieliśmy for us? Shouldn't the stem be the same?
This is a special feature of the verb mieć (to have) in the past tense. In most past tense forms, the e from the dictionary form changes to a, which is why he had translates to miał. However, for plural groups that include at least one man (the masculine personal form), the stem keeps the e, giving us mieliśmy (we had).
Do other verbs do this change from e to a in the past tense?
Yes! You will see this e/a alternation in several common verbs ending in -eć. For example, rozumieć (to understand) becomes rozumiał (he understood) but rozumieliśmy (we understood), and wiedzieć (to know) becomes wiedział but wiedzieliśmy.
The word for dog is psa in both halves of the sentence. Is it the exact same case both times?
Surprisingly, no! In the first half (miał psa), it is the Accusative case because it is the direct object of a positive verb, and pies is an animate masculine noun. In the second half (nie mieliśmy psa), it is the Genitive case because Polish requires the Genitive for direct objects when the verb is negated. It just so happens that for pies, the Accusative and Genitive forms look exactly the same!
Why does the word for dog become and not piesa?