Final answer:
Verbs with stem changes in the subjunctive mood also have a stem change in the nosotros and vosotros forms.
Step-by-step explanation:
Verbs with stem changes in the subjunctive mood also have a stem change in the nosotros and vosotros forms. For example, the verb 'dormir' (to sleep) has a stem change from 'o' to 'u' in the subjunctive mood, so 'durmiéramos' and 'durmierais' are the correct forms in the nosotros and vosotros forms.