Table 1 uses actual verbs to demonstrate some -ar, -er, and -ir endings. Pay close attention to stem-changing verbs in all the different forms. The vosotros/vosotras command forms that were explained earlier are so unusual that they're not included in the following charts. You can always use the ustedes command form when you are speaking to a group of people. Since the ustedes form relays an attitude of respect and is easier to form, you can't go wrong. It is important to review the explanation of vosotros command forms so that you can recognize what is being said if someone gives you a command in this form, but keep things simple and use the ustedes command forms when you are speaking to a group.
Three common -go verbs also fall under another irregular category called stem-changing verbs. The irregular -go ending of the yo form follows to keep the list of -go verbs together.
A verb that ends in -go in the yo form will keep the g when you drop the -o to form usted, ustedes, and the negative tú command forms. In addition, they generally have irregular affirmative tú command forms. Table 2 includes all of the command forms for the most common -go verbs.
Several verbs that end in -zco in the yo form of the present tense were presented in the "Irregular Verbs in the Present Tense" articles. Review those verbs, and then take a look at Table 3 to see how the command forms are affected.
"The Preterit Tense" articles introduced the concept of changing the spelling of a verb to maintain the correct pronunciation. You learned a list of common verbs that end in -car, -gar, or -zar because when you conjugate verbs in the preterit tense, the yo form has an ending that requires you to change the spelling of any verb that ends in -car, -gar, or -zar.
That same spelling change is necessary when you add the "opposite endings" to create a command form. If a verb ends in -car, change c to qu in all command forms except the tú affirmative. If a verb ends in -gar, change g to gu in all command forms except the tú affirmative. If a verb ends in -zar, change z to c in all command forms except the tú affirmative.
A comprehensive list of the command forms of common verbs with spelling changes is provided in Table 4. Some of these verbs are also stem changers, so look carefully at every form.
If a verb has a truly irregular yo form in the present tense, all of the command forms will also be completely irregular. Table 5 is a list of all the truly irregular command forms.