DIFFERENT TENSES - DIFFERENT MEANINGS


These verbs change their meaning when used in the preterit and the past progressive: 


conocer ('a' + person):
	Present:  to know (someone), be acquainted with -   Conozco a ella.
	Preterit:  met/began to know (someone or some place) -  Conociste a ella.
	Imperfect/Past Progressive:  knew (someone); was acquainted with  -  Conocia a ella.


saber (+ information): 
	Present:  to know  (something)
	Preterit:  found out  (something)
	knew  (something)


querer (+ infinitive):
	Present:  to want  (to do something)
	Preterit:  tried to, but did not  (do something)
	Imperfect/Past Progressive:  wanted (to do something)


no querer (+ infinitive):           
	Present:  not to want  (to do something)
	Preterit:  refused  (to do something and did not)
	Imperfect/Past Progressive:  did not want to  (to do something)


poder (+ infinitive):
	Present:  to be capable (of doing something)
	Preterit:  was/were able and did  (do something)
	Imperfect/Past Progressive:  was/were capable  (of doing something)


no poder (+ infinitive): 
	Present:  not to be capable (of doing something)
	Preterit:  was/were not able and did not (do something)
	Imperfect/Past Progressive:  was/were not capable   (of doing something)


tener que (+ infinitive): 
	Present:  to have to   (do something)
	Preterit:  had to and did (do something)
	Imperfect/Past Progressive:  had to, was supposed   (do something), but did not necessarily do it.


ir a (+ infinitive): 
	Present:  to be going to (do something)
	Preterit:  was/were going to (do something), but did not necessarily do it
	Imperfect/Past Progressive:  Expresses a past plan that did not materialize. Can be used to give excuses.