Translation: Miguel and Elena (to close) the door.
The infinitive must be conjugated according to the subject, which is plural (Miguel and Elena). It must also be in present tense. The conjugation of cerrar for a plural subject in present tense indicative is cierran.
Nosotros podríamos ir a ver una Película. Nosotros podemos ir a un parque de diversiones. Nosotros tal vez podamos salir a comer. Nosotros podíamos patinar en hielo.
