Irregular 'AR' Verbs: Spelling Changes 'CAR'-'QU'
Spanish: Cambridge International GCSE, topic 10.6.6
Spelling Changes ('CAR' → 'QU')
To preserve the sound 'k', verbs that end in 'car' change ‘c’ to 'qu' in the subjunctive. For example:

Buscar - to look for, to search
- Busque - look for.
- Busques - you look for.
- Busque - he/she looks for / you look for (formal).
- Busquemos - we look for.
- Busquéis - you look for (plural).
- Busquen - they look for / you look for (formal plural).

Sacar - to take out, to get
- Saque - I take.
- Saques - you take.
- Saque - he/she takes / you take (formal).
- Saquemos - we take.
- Saquéis - you take (plural).
- Saquen - they take / you take (formal plural).

Publicar - to publish
- Publique - I publish.
- Publiques - you publish.
- Publique - he/she publishes / you publish (formal).
- Publiquemos - we publish.
- Publiquéis - you publish (plural).
- Publiquen - they publish / you publish (formal plural).
Test yourself on Irregular 'AR' Verbs: Spelling Changes 'CAR'-'QU'
How do you say 'we take' in the present subjunctive in Spanish?
How do you say 'I publish' in the present subjunctive in Spanish?