It's important to note that "main verb" is not a part of speech itself. It's a term used to describe the most important verb in a sentence. It's the verb that conveys the action or state of being of the subject.
Here's how to identify the main verb:
1. Identify the subject: Who or what is performing the action?
2. Ask yourself what the subject is doing or being: This will give you the main verb.
Example:
* The dog barks loudly.
* Subject: The dog
* Main verb: barks
Let me know if you'd like more examples!