The verb oír means to hear.
It is irregular in the preterite.

Yo oí una voz en la oscuridad.
      I heard a voice in the dark.

¿Dónde oíste eso?
      Where did you hear that?

Juan oyó el ruido.
      Juan heard the noise.

¿Usted oyó hablar de ese proyecto?
      Did you hear talk about that project? (formal)

No le oímos salir.
      We did not hear him leave.

Vosotros oísteis que el anticristo viene.
      You guys heard that the antichrist is coming.

Ellos oyeron los gritos de la gente.
      They heard the screams of the people.

¿Oyeron esos gritos?
      Did you all hear those shouts? (formal)

Preterite sentences with oí
Preterite sentences with oíste
Preterite sentences with oyó
Preterite sentences with oímos
Preterite sentences with oyeron