Estar imperfect conjugation

 Estar means to be.
  It is regular in the imperfect.
   We use imperfect instead of preterite to refer
    to something with no definite beginning or end.

Sentences using estar in the imperfect tense

Yo estaba estudiando.
     I was studying.

¿Estabas corriendo cuando te vi?
     Were you running when I saw you?

Él estaba cantando bajo la lluvia.
     He was singing in the rain.

Todos estábamos preocupados por el examen.
     We were all nervous about the exam.

Vosotros estabais con el director.
     You all were with the principal.

Estaban muy enojados.
     They were very angry.