Gramática: What ______ you do yesterday in the evening? I was in the library.

1. A frase tem o marcador de passado “yesterday” (ontem), então o auxiliar deve estar no passado.
2. Em perguntas no passado simples, usamos a estrutura: $\text{Did} + \text{sujeito} + \text{verbo base}$.
3. Portanto: “What did you do yesterday in the evening?”

Alternativa correta: (b).