CAR, GAR, ZAR verbs

In the preterit, verbs that end in CAR, GAR or ZAR have a spelling change in the YO form. The spelling changes in order to keep the pronunciation the same. 
 

What are the changes?

• With –CAR verbs, the C changes to a QU.
• With –GAR verbs the G changes to a GU.
• With –ZAR verbs the C changes to a Z.

Examples

Buscar- Ayer yo busqué un trabajo.

Llegar- Ayer yo llegué tarde.

Almorzar- Ayer yo almorcé con mis amigas