Verbs that change meaning in the preterite

Question 1

How does conocer change in meaning, with examples, from present to preterite?

Answer 1

Present = Conozco a esa pareja / I know that couple.
Preterite = Conocí a esa pareja ayer / I met that couple yesterday.

Question 2

How does saber change in meaning, with examples, from present to preterite?

Answer 2

Present = Sabemos la verdad / We know the truth
Preterite = Supimos la verdad anoche / We found out the truth last night

Question 3

How does poder change in meaning, with examples, from present to preterite?

Answer 3

Present = podemos hacerlo / We can do it
Preterite = pudimos hacerlo ayer / We managed to do it yesterday

Question 4

How does querer change in meaning, with examples, from present to preterite?

Answer 4

Present = Quiero ir, pero tengo que trabajar / I want to go, but I have to work
Preterite = Quise evitarlo, pero fue imposible / I tried to avoid it, but it was impossible

Question 5

How does poder change, in meaning, in the preterite, from positive to negative?

Answer 5

pude = I managed (to)
no pude = I failed (to)

Question 6

How does querer change, in meaning, in the preterite, from positive to negative?

Answer 6

quise = I tried (to)
no quise = I refused (to)