Querer - imperfect
wanted
Querer - preterite - positive
tried (but failed)
Querer - preterite - negative
refused
Poder - imperfect
was able to, could
Poder - preterite - positive
succeeded
Poder - preterite - negative
could not
saber - imperfect
knew
saber - preterite
found out, discovered
conocer - imperfect
knew (already)
conocer - preterite
met