demostrasteis

Demostrasteis is the second-person plural form of the Spanish verb demostrar in the pretérito perfecto simple (preterite) indicative mood, used to say “you all demonstrated.” It corresponds to the verb form vosostros demonstrasteis in Spain and is commonly found in informal address to a group of people. The verb demostrar belongs to regular -ar verbs, so demostrasteis is formed from the stem demostr- plus the ending -asteis, indicating a completed past action.

In meaning, demostrar can express both proving something and showing how something works. In the pretérito, demostrasteis signals that the act of proving or showing was finished at a specific time in the past, often tied to a particular event or demonstration. The form is standard in Spain, where the pronoun vosotros is used, but it is not commonly used in much of Latin America, where ustedes would typically be employed for past actions with the corresponding form demostraron.

Usage notes include the regional variation in pronoun choice. When addressing a group informally in Spain, demostrasteis is appropriate; in most other Spanish-speaking regions, you would use demostraron with ustedes. The vosotros form may appear in narratives, literature, or regions that preserve traditional forms.

Examples:

- Ayer, vosotros demostrasteis la hipótesis con datos experimentales.

- Durante la reunión, demostrasteis cómo funciona el método paso a paso.

Etymology: derived from demostrar, from Latin demonstrare. See also: demostrar (infinitive), demostrasteis in conjugation tables, pretérito vencible forms of -ar verbs.