Here's why:
* Transitive verbs require a direct object to complete their meaning. They express an action that is done *to* something.
* Example: "She wrote a letter." (The action of "wrote" is done to the "letter.")
* Intransitive verbs do not require a direct object. They express a complete action without needing anything to receive the action.
* Example: "The dog barked." (The action of "barked" is complete without needing anything to receive it.)
In summary: If a verb can be followed by a direct object (the receiver of the action), it's a transitive verb.