saber (preterite) - to find out

saber (imperfect) - to know

conocer (preterite) - to meet

conocer (imperfect) - to be familiar with; know a person or place

tener (preterite) - to get; aquire

tener (imperfect) - to have

poder (preterite) - to manage

poder (imperfect) - to be able to

no poder (preterite) - to not manage; to try and then fail

no poder (imperfect) - to be unable to

no querer (preterite) - to refuse

no querer (imperfect) - to not want