Explanation:
Saque la basura.
Take out the garbage.
This sentence is correct because it's in the third person singular form, in the subjunctive, present tense, which indicates it is a formal command. When it comes to formal commands, we use USTED and USTEDES. The tenses we use -- we always use SUBJUNCTIVE present tense, in the third person singular and third person plural form.
Vamos a descansar después de la cena.
