Answer:
"until the boss told him to go home"
Explanation:
Eric worked until the boss told him to go home.
Also referred to as a dependent clause, a subordinate clause is one which complements a sentence's main clause. I've underlined the main clause and italicized the subordinate clause. You can see that "Eric worked" could stand alone as a sentence, but "until the boss told him to go home" could not.
