Semantic Roles
Also called "Thematic roles". And is the underlying relationship that a participant has with the main verb in a clause.
Goal
Where the agent moves to.
Johan swam to the raft.
Source
Where the entity moves from.
Jessy is from Toronto.
Location
An entity is in the description of an event.
The paper is in the folder.
Experiencer
When a noun phrase is used to designate an entity as the person who has a feeling, perception or state.
Did you hear what noise?
Instrument
If an agent uses another entity in order to perform an action.
He drew the picture with a crayon.
Theme
The entity is involved in or affected by the action
Agent
Is the entity that performs the action, in short words is a person or thing who is the doer of an event.
Example
The boy kicked the ball.