Tú answer una tarjeta postal. (recibir)
ustedes answer un café con leche. (beber)
carmen answer la puerta con llave. (abrir)
yo answer la torta. (comer)
yo answer por la escalera. (subir) (1 point)
here you have to fill the blank with the correct form of the verb in the preterite.

Tú recibiste una tarjeta postal.

Ustedes bebieron un café.

Yo comí la torta.

Yo subí por la escalera.

Explanation:

Tú recibiste una tarjeta postal. This means: you received a postcard. Recibiste is the preterite of the verb recibir in the second person of the singular.

Ustedes bebieron un café. This means: You drunk coffee. Bebieron is the preterite of the verb beber in the second person of the plural.

Yo comí la torta. In English this means: I ate the cake. Comí is the preterite of the verb comer in the first person of the singular.

Yo subí por la escalera. This means I went up the stairs. Subí is the preterite of the verb subir in the first person of the singular.