Using the Preterite and the Imperfect

This is a bit of a review (again), about the use of the preterite and the imperfect. Particularly on when to use one vs. another.

The preterite tells you about an action that started and ended at a definite time.

• Ocurrió un temblor. (An earthquake took place.)
• El temblor ocurrió a las 7:19 de la mañana. (The earthquake took place at 7:19 in the morning.)
• Muchos edificios se cayeron. (Many buildings fell down.)

*Note how the earthquake started and ended.

The imperfect tells about past actions without saying when they begin or end.

• Todo el mundo dormía. (Everybody was sleeping.)
• La tierra temblaba. (The earth was shaking.)
• Había gente por todas partes. (There were people everywhere.)

*Note that you can't tell when the actions started or ended.

You can use both tenses to talk about something that happened (preterite) while something else was going on (imperfect).

Nos enamoramos. Éramos jóvenes.
We fell in love. We were young.
Nos enamoramos cuando éramos jóvenes.
We fell in love when we were young.

Note. Ordinals are placed before nouns and agree with the nouns in gender and number.
el quinto semana la segunda semana

Primero and tercero drop the o before a masculine singular noun.

el primer día