El uso del Imperfecto 

Whether you should use the preterite or the imperfect depends in a large extend on the meaning of the verb that you are using. 

There are basically two kinds or verbs:

  • action and punctual verbs like  golpear (to hit), saltar (to jump), comprar (to buy), vestirse (to get dressed) etc., verbs used to say that someone is doing something and that what you are doing implies somehow movement or change, and that the action is relatively short
  • verbs of state like ser (to be), estar (to be), querer (to want), tener (to have) etc., verbs used to describe longer lasting conditions or states.
Again, this is only a rule of thumb because there is no clear cut between action verbs and verbs of state, and depending upon the context the same verb can be interpreted a describing a state or an action, but as ageneral rule we can say

1. state verbs or non action verbs are essentially used in imperfect :

Yo tenía una familia muy unida. (I had a very united family.)  Nosotros éramos una familia unida. (We were a united family.)

ojo2.gif - 639 BytesIf you are using the preterite with state verbs, like estar, ser, tener, querer, saber, conocer, poder, etc you are implying somwhow a time limit or time frame, which might change the original meaning of the state verb, making it an action verb. (see Preterite use)

Mi madre tenía tres hijos. (My mother had three children.) but: Mi madre tuvo tres hijos. (There could be to interpretations or meanings in different contexts: 1. My mother gave birth to three children or that one or several of the children died.)
2. using the imperfect with action verb implies that you did the action repeatedly or habitually, over an unspecified period of time:
Melevantaba a las 7, me duchaba, desayunaba e iba a clase. (I used to get up at 7, take a shower, eat breakfast and go to class.)

But the important thing here is the unspecified time frame. Repetition can also be seen as a completed series. In this case again you use the preterite:

En 1999 todos los días me levanté a las 7, me duché, desayuné y fui a clase. (In 1999, every day I got up at 7, took a shower, ate breakfast and went to class.)

Therefore use the imperfect to:

  • describe what you habitually did in the past, or what you used to do
Cuando era niño siempre iba a la escuela, jubaga con mis amigos y miraba dibujos animados. (When I was a child I used to go to school, play with my friends and watch cartoons.)
  • describe physical and mental conditions or states in the past, how someone felt or looked
No me sentía bien, me dolía la cabeza, y mis amigos se dieron cuenta de que tenía un problema. (I didn't fell good, I had an headache, and my friends realized that I had a problem.)
  • describe weather conditions
Hacía buen tiempo y el sol brillaba. (The weather was nice and the sun was shining.)
  • describe the background, the setting of an event or what someone was doing when something happend.
El estaba cubierto de sangre y todavía tenía el cuchillo en la mano cuando entró su novia. (He was covered with blood and he still had the nive in his hand when his girl friend entered.)
  • tell time in the past
Eran las tres cuando finalmente llegó la policía. (It was three a clock when the police arrived finally.)
3. You also use the imperfect to shift the present or the near future to the past in an indirect speach act, for example when you are quoting someone:
Direct speach: "Te odio" ("I hate you.")   Quote: Juan, tu novia me dijo que te odiaba. (Juan, your girl friend told me that she hated you.)

Direct speach: "Te voy a matar" ("I'll kill you.")  Quote: Juan, tu novia me dijo que te iba a matar. (Juan, your girl friend told me that she would/ or was going to kill you.)