Fully irregular subjunctive verbs
While most verbs form the present subjunctive by swapping their standard endings, a handful of very common verbs have fully irregular bases that you simply have to memorize.
For ir (to go) and ser (to be), the present subjunctive bases are vaya and sea.
| The rule is that you go in uniform. | La norma es que vayas con el uniforme. |
| I advise you to be very polite with the client. | Te aconsejo que seas muy educado con la clienta. |
The subjunctive of dar and haber
The verb dar (to give) uses the base dé. The written accent on the yo and él/ella/usted forms distinguishes it from the preposition de (of/from). Notice that the tú form (des) does not need an accent.
| I demand that the boss give permission to the employee. | Exijo que la jefa le dé permiso a la empleada. |
| I suggest that you give the gift to your grandmother. | Te sugiero que le des el regalo a tu abuela. |
The auxiliary verb haber becomes haya. You will frequently see this as the subjunctive equivalent of the impersonal hay (there is / there are).
| It is essential that there be punctuality in the office. | Es esencial que haya puntualidad en la oficina. |
The subjunctive of estar and saber
For estar (to be), the subjunctive base is esté. Pay close attention to the spelling: most forms require a written accent mark (like esté, estés, and estén).
| I want you to be attentive to every detail. | Quiero que estés atento a cada detalle. |
Finally, the verb saber (to know) uses the base sepa.
| It is better that you know the answer. | Es mejor que sepas la respuesta. |
