Verbos con cambio ortográfico z > c (pretérito Indefinido)

Stem-changing Spanish z>c in the simple past tense

Spanish verbs ending in -zar undergo a change when they are conjugated in the simple past.
The -z changes to -c but it only affects the yo form.
For example: 
almorzar (to have lunch)-> yo almorcé
gozar (to enjoy) -> yo gocé
To see a list of verbs affected by this irregularity go to List of Spanish -zar verbs that change z>c in the preterite for the yo form.
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