Irregular preterite stems

Just like tener and estar, several other common verbs use irregular stems in the preterite. They share the same special endings (-e, -iste, -o, -imos, and -ieron), and they never use accent marks.

The "u" stems: poner, poder, and saber

These verbs change their stem vowels to u.

Pronounponer (pus-)poder (pud-)saber (sup-)
yopusepudesupe
pusistepudistesupiste
él / ella / ustedpusopudosupo
nosotros / nosotraspusimospudimossupimos
ellos / ellas / ustedespusieronpudieronsupieron

Tip: In the preterite, saber often means "to find out" or "to learn" (a fact), and poder usually means someone "managed to" or "was able to" do something.

The king put his gold treasure here.
El rey puso su tesoro de oro aquí.
I was able to discover something older than that ruin.
Yo pude descubrir algo más antiguo que esa ruina.
We didn't find out anything about the history of the treasure.
Nosotros no supimos nada de la historia del tesoro.

The "i" stems: venir, querer, and decir

These verbs change their stem vowels to i.

Pronounvenir (vin-)querer (quis-)decir (dij-)
yovinequisedije
vinistequisistedijiste
él / ella / ustedvinoquisodijo
nosotros / nosotrasvinimosquisimosdijimos
ellos / ellas / ustedesvinieronquisierondijeron

Notice the spelling of dijeron. Because decir has a stem ending in j (dij-), it drops the i from the normal -ieron ending. You will always use -eron for irregular preterite stems that end in j.

The researchers came to the ancient tomb.
Los investigadores vinieron a la tumba antigua.
They wanted to bury the king under the stone.
Ellos quisieron enterrar al rey debajo de la piedra.
Who told you that they buried the gold in the ground?
¿Quién te dijo que enterraron el oro en la tierra?