Subject: "They" performs the action of the verb.
* Example: "They went to the store." ("They" is the subject, performing the action of "went")
Object: "They" receives the action of the verb.
* Example: "The dog chased them." ("They" is the object, receiving the action of "chased")
To determine if "they" is a subject or object, look at the verb and see who is doing the action and who is receiving the action.