Explain how stem-changing –ir verbs are different from stem-changing –ar and –er verbs in the present subjunctive..
In the present subjunctive, stem-changing –ir verbs follow a slightly different pattern compared to stem-changing –ar and –er verbs. Most stem-changing –ir verbs undergo a stem change in all forms of the present subjunctive except for the nosotros and vosotros forms. This means that the stem change will occur in the yo, tú, él/ella/usted, and ellos/ellas/ustedes forms, but not in the nosotros and vosotros forms.
For example, the verb "dormir" (to sleep) changes from dormir to duerma, duermas, duerma, duerman, and then back to dormir for the nosotros and vosotros forms in the present subjunctive.
On the other hand, stem-changing –ar and –er verbs usually follow a consistent stem change pattern in all forms of the present subjunctive, including the nosotros and vosotros forms.
Overall, the main difference between stem-changing –ir verbs and stem-changing –ar and –er verbs in the present subjunctive is the inconsistency of stem changes in the nosotros and vosotros forms for –ir verbs.
use simpler terms
In the present subjunctive, most stem-changing –ir verbs change their stems in all forms except for "we" and "you all." This means that the verb will have a different stem for "I," "you," "he/she/you (formal)," and "they/you all," but will go back to the original stem for "we" and "you all."
In contrast, stem-changing –ar and –er verbs typically have a consistent stem change in all forms of the present subjunctive, including "we" and "you all."
So, the main difference is that stem-changing –ir verbs have an irregular stem change pattern in the present subjunctive, while stem-changing –ar and –er verbs have a more regular pattern.