The present subjunctive is typically formed using the present tense yo form. For verbs with irregular yo forms, this irregularity carries over to the entire subjunctive conjugation. Other common verbs are completely irregular.
Verbs with Irregular "Yo" Forms
Verbs like tener (to have) and hacer (to do/make) are irregular in the present yo form (tengo, hago). Because the subjunctive is built from that stem, you drop the -o and add the opposite endings for the entire conjugation.
| Pronoun | tener | hacer |
|---|---|---|
| yo | tenga | haga |
| tú | tengas | hagas |
| él / ella / usted | tenga | haga |
| nosotros / nosotras | tengamos | hagamos |
| ellos / ellas / ustedes | tengan | hagan |
| It is important that the foreign passport has the signature. | Es importante que el pasaporte extranjero tenga la firma. |
| The consul recommends that the citizen do the paperwork here. | El cónsul recomienda que el ciudadano haga el trámite aquí. |
| It is necessary that we do the paperwork. | Es necesario que hagamos el trámite. |
Completely Irregular Verbs
Verbs whose present yo form doesn't end in -o (like soy and voy) have completely irregular stems in the subjunctive.
- ser (to be): sea, seas, sea, seamos, sean
- ir (to go): vaya, vayas, vaya, vayamos, vayan
| I want the document to be valid. | Quiero que el documento sea válido. |
| It is necessary that you go to the embassy today. | Es necesario que vayas a la embajada hoy. |
| It is better that you go to the embassy with the copy. | Es mejor que usted vaya a la embajada con la copia. |
Subjunctive vs. Infinitive
Use the subjunctive when there is a change of subject (e.g., It is necessary that YOU go). If you are stating a general rule or requirement without specifying a person, use the infinitive. Expressions like hay que (one must) are perfect for this.
| To apply for the visa, one must bring a copy. | Para solicitar la visa, hay que llevar una copia. |