1. Base Form: This is the simplest form of the verb, the one you find in the dictionary. Examples: *walk*, *eat*, *sing*.
2. Present Participle (or -ing form): This is formed by adding "-ing" to the base form. Examples: *walking*, *eating*, *singing*.
3. Past Tense: This form indicates an action that happened in the past. Examples: *walked*, *ate*, *sang*.
4. Past Participle: This form is used in perfect tenses (like present perfect and past perfect) and passive voice. It can sometimes be the same as the past tense, but not always. Examples: *walked*, *eaten*, *sung*.
5. Simple Present: This is the form used for present actions, habitual actions, or facts. It can be the same as the base form (for most verbs), or have an -s ending for third person singular subjects. Examples: *walk*, *eats*, *sings*.
Keep in mind that there are also different verb tenses, which are built using the verb forms, auxiliary verbs, and other grammatical elements. These tenses express the time and aspect of an action.