Usted' can be shortened to 'Ud' and 'ustedes' can be shortened to 'Uds'. Irregular verbs in the present tense in Spanish Irregular verbs don’t follow the usual pattern in the present tense.

Reflexive verbs close reflexive verb Verbs where the action is done to the same person who is doing it, eg se laver (to wash oneself). describe an action that you do to yourself or that reflects ...

but the most common one you will use besides the present tense will be the past tense. Normally in the past tense, you do not need to worry about subject-verb agreement because you can conjugate most ...