1. Verbs are words that express actions or states of being. In English, verbs can be changed to reflect the time at which an action or state of being occurs. These changes are known as verb tenses.

2. Verb tenses are the different forms of verbs that indicate the time at which an action or state of being occurred. There are three main verb tenses in English: past, present, and future. Each of these tenses can be further divided into different forms, such as simple, continuous, perfect, and perfect continuous.