- Identify the verb type-AR, ER and IR and then remove the ending.
- Identify the vowel of the stem.
- Change the vowel in the following way:
E>I
O>UE
U>UE
This does not happen in the first and second person plural.
e.g. Pensar-To Think
Pienso pensamos
Piensas pensáis
Piensa piensan