AUXILIAR VERB - DID. FOR QUESTIONS AND NEGATIVE DO-->DID DID I/YOU/HE/SHE/IT/THEY/WE...? I/YOU/HE/SHE/IT/THEY/WE DIDN'T I didn't / Did I...? you didn't / Did you...? She didn't / Did she...? He didn't / Did he...? It didn't / Did it...? We didn't / Did we...? They didn't / Did they...? VERY IMPORTANT!! When you use an auxiliar, the verbs keep in present:
I bought a present for you (positive)
I didn't bring a present for you (negative) Did you bring a present for me? (question)