The Irregular Spanish Subjunctive (Verbs With CAR GAR ZAR Endings)

You may remember when studying the past tense that verbs ending in CAR GAR or ZAR had spelling changes in the YO form.

In the Spanish subjunctive, those same spelling changes happen only in ALL the verb forms.

For verbs ending in CAR like buscar, the C changes to a QU.

busque          busquemos
busques
busque          busquen

for verbs ending in GAR like pagar, the G changes to GU.

pague          paguemos      
pagues
Pague          paguen

For verbs ending in ZAR like cruzar, the Z changes to a C

cruce           crucemos
cruces
cruce           crucen



Just like in the preterite, imagine a ZCAR in  a  CAR screaming "GARrrrr" but instead of driving through only the YO forms, he is completely out of control ( so is the subjunctive in my opinion) and he is driving through all verbs forms.