The first step to using the subjunctive present tense is learning to create the conjugated forms of a verb in the present subjunctive. Because it is a present tense, the present subjunctive is based on the forms of the present tense that you already know. If you know all the irregularities of the indicative present tense, you will find the present subjunctive an easy tense to conjugate.
Creating present subjunctive verb forms
There are three steps you can chant when creating a present subjunctive verb form:
1. form of yo
2. drop the ‐o
3. add the opposite endings
Of course, chanting the above does no good if you do not understand what it means in application. First of all, you must think of the yo form of the indicative present tense that you already know. For 99.9% of Spanish verbs, you simply drop the ‐o ending of the yo form and add a present tense subjunctive ending to what is left. (Only a few verbs in the Spanish language have a yo form that doesn't end in ‐o, and all these are irregular in the present subjunctive. You'll learn those later.) Because the yo form no longer ends in ‐o, the present subjunctive yo form looks exactly like the él/ella/Ud. form. Use the appropriate subject pronoun to specify the subject. The reason the “chant” says to add the opposite endings is because ‐er and ‐ir verbs use ‐ar verb endings, and you must use the normal ‐er endings with ‐ar verbs.
Present subjunctive of - ar verbs
Table , below, will help you understand that the verb endings used for ‐ar verbs in the present tense subjunctive are like those used for the regular present tense of ‐er verbs.
Look over the present subjunctive conjugations of the regular ‐ar verb escuchar in Table .
Verbs that end in -car, -gar, and -zar
Any verb that ends in ‐car, ‐gar, or ‐zar will use the endings and rules explained above for creating the present subjunctive, but to preserve the correct pronunciation of that letter, it will undergo a spelling change in the letter that precedes the subjunctive ending. You learned about a similar spelling change in the preterit tense that happens for the same reason, but in the preterit, this spelling change affects only the yo form. In the present subjunctive, the spelling change occurs in all forms.
To maintain the hard c sound (like a k), use qu rather than c in all forms of the present subjunctive for any verb whose infinitive form ends in ‐car.
Table provides the subjunctive forms of common ‐car verbs. Because the él form is the same as the yo form, it is not listed.
To maintain the hard g sound (like the g in “go”), use gu rather than g in all forms of the present subjunctive for any verb whose infinitive form ends in ‐gar.
The verbs in Table undergo the g to gu spelling change in all forms of the subjunctive. If the verb is a stem‐changer, the change will be apparent in all forms but nosotros/nosotras and vosotros/vosotras. Because the él form is the same as the yo form, it is not listed.
There is a consistent rule in Spanish that dictates that the letter z change to a c when followed by an e. This spelling change occurs in every subjunctive conjugated form of any verb that ends in ‐zar.
Look at the conjugation chart in Table and use it as an example for the ‐zar verbs in Table .
Table provides the subjunctive forms of common ‐zar verbs. Because the él form is the same as the yo form, it is not listed.
Notice that ‐ar verbs do not undergo a stem change in the nosotros/nosotras or vosotros/vosotras forms but do undergo a stem change in all other forms.
Present subjunctive of - er and - ir verbs
The earlier chant still applies when you conjugate ‐er and ‐ir verbs in the subjunctive present tense:
1. form of yo
2. drop the ‐o
3. add the opposite endings
As you can see in Table , the endings for ‐er and ‐ir verbs in the present subjunctive look like the ‐ar endings in the regular (indicative) present tense, except that the yo form is exactly like the él form.
The verb escribir is a regular ‐ir verb so, in the present subjunctive, it takes regular ‐ar endings (see Table ).