Teacher:In this task you are given a sentence. You must judge whether the main verb of the sentence is in present or past tense. Label the instances as "Present" or "Past" based on your judgment. If there is no verb in the given text, answer "Present".
Teacher: Now, understand the problem? Solve this instance: They established a hasty perimeter around the downtown area, mainly using additional men or teenage boys who volunteered to help instead of evacuate.
Student:
Past