Irregular 'AR' Verbs: Spelling Changes 'ZAR'-'C'
Spanish: Cambridge International GCSE, topic 10.6.7
Spelling Changes ('ZAR' → 'C')
Verbs ending in ‘zar’ all have irregular stems in the present subjunctive for spelling reasons. Change the ‘z’ for a ‘c’. For example:

Alcanzar - to reach
- Alcance - I reach.
- Alcances - you reach.
- Alcance - he/she reaches / you reach (formal).
- Alcancemos - we reach.
- Alcancéis - you reach (plural).
- Alcancen - they reach / you reach (formal plural).

Almorzar - to have lunch
- Note that 'almorzar' is irregular in the present tense and keeps that pattern as well.
- Almuerce - I have lunch.
- Almuerces - you have lunch.
- Almuerce - he/she has lunch / you have lunch (formal).
- Almorcemos - we have lunch.
- Almorcéis - you have lunch (plural).
- Almuercen - they have lunch / you have lunch (formal plural).

Comenzar - to start
- Note that 'comenzar' is irregular in the present tense and keeps that pattern as well.
- Comience - I start.
- Comiences - you start.
- Comience - he/she starts / you start (formal).
- Comencemos - we start.
- Comencéis - you start (plural).
- Comiencen - they start / you start (formal plural).
Test yourself on Irregular 'AR' Verbs: Spelling Changes 'ZAR'-'C'
How do you say 'they start' in the present subjunctive in Spanish?
How do you say 'she reaches' in the present subjunctive in Spanish?